Which of the following pairs of compounds has a different Effective Atomic Number (EAN) ?

D) $[Fe(NH_3)_6]^{2+}, [Cr(C_2O_4)_3]^{3-}$

Predict the correct order of isoelectronic species

A) $N^{3-} > O^{2-} > F^- > Na^+$

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100 questions with answersProvisional keyEnglish

Technical Assistant - Drugs Control Dept question paper 2026

Date of test: 04-11-2026
Question paper code: 75/26
Category No.: 615/2025
Questions: 100
Answer key: Provisional Answer Key
Exam mode: OMR (pen and paper)

Provisional key. Kerala PSC can change answers after reviewing complaints; the final key decides the marks.

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Source: Kerala PSC (keralapsc.gov.in) · official document· Last updated 6 Nov 2026· How we check content· ⚑ Report a problem

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All 100 questions with answers

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1.
The radiant energy emitted or absorbed discontinuously in the form of tiny bundles of energy is known as
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Answer: A —
Quanta
The discrete packets of energy are called quanta.
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2.
The emission of photoelectrons due to light of a certain frequency is proportional to
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Answer: B —
Intensity of light
The number of photoelectrons emitted is directly proportional to the intensity of the incident light.
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3.
Every orbital in a sub level is singly occupied before any orbital is doubly occupied is suggested by
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Answer: C —
Hund
Hund's rule of maximum multiplicity states that electrons fill degenerate orbitals singly before pairing.
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4.
Organize the following based on the ascending order of covalency – $LiF$ , $NaCl$ , $NaBr$ , $NaI$
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Answer: A —
$LiF < NaCl < NaBr < NaI$
According to Fajan's rule, covalency increases as the size of the anion increases.
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5.
The shape of $BeF_2$
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Answer: D —
linear
$BeF_2$ has $sp$ hybridization and a linear geometry.
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6.
Electronegativity is calculated using which of the following scale ?
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Answer: D —
All of the above
Pauling, Mulliken, and Allred-Rochow are all established scales for measuring electronegativity.
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7.
The bond order of $CO_2$ is
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Answer: A —
2
In $O=C=O$ , each $C-O$ bond is a double bond, so the bond order is 2.
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8.
The inductive effect acts only through
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Answer: A —
Sigma bond
The inductive effect is the permanent displacement of shared electron pairs along a chain of sigma bonds.
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9.
The most common nuclear fuel used is
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Answer: C —
$U-235$
$U-235$ is the most common fissile isotope used as nuclear fuel.
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10.
Among the compounds listed, which one exhibits the smallest bond angle within its molecular structure ?
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Answer: C —
$H_2S$
$H_2S$ has a bond angle of approximately $92^{\circ}$ , which is smaller than the others listed.
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11.
Which of the following statement is/are correct for ferrocene ? i. The dipole moment of the eclipsed form of ferrocene is zero. ii. The dipole moment of the staggered form of ferrocene is non-zero. iii. Ferrocene has $\pi$ delocalized molecular orbitals. iv. Ferrocene cannot be hydrogenated under normal conditions, nor does it undergo the diels-Alder reaction.
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Answer: C —
i, iii, iv
All statements regarding the structural and chemical properties of ferrocene are correct.
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12.
Which of the following pairs of compounds has a different Effective Atomic Number (EAN) ?
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Answer: D —
$[Fe(NH_3)_6]^{2+}, [Cr(C_2O_4)_3]^{3-}$
Calculating EAN for $[Fe(NH_3)_6]^{2+}$ gives $26-2+12=36$ , while $[Cr(C_2O_4)_3]^{3-}$ gives $24-3+12=33$ .
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13.
Ziegler-Natta catalysts are i. Heterogeneous catalysts ii. Homogeneous catalysts iii. made by treating Titanium tetrachloride with triethyl aluminium iv. Catalysts for polymerization of alkenes at atmospheric pressure and ambient temperature.
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Answer: B —
i, iii, iv
Ziegler-Natta catalysts are typically heterogeneous, made from $TiCl_4$ and $Al(C_2H_5)_3$ , and used for alkene polymerization.
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14.
Which of the following statement/s incorrectly describes the role of $Zn^{2+}$ in carbonic anhydrase ? i. Carbonic anhydrase catalyses the interconversion of $CO_2$ and carbonates. ii. Carbonic anhydrase cleaves the carbonyl terminal amino acid from a peptide chain. iii. Coordinated by two histidine residues, one glutamate and a water molecule. iv. Pancreatic digestive enzyme.
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Answer: C —
ii, iii, iv
Statements ii and iv are incorrect descriptions of carbonic anhydrase.
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15.
Which of the following complexes is/are square planar ? i. $[PdCl_4]^{2-}$ ii. $[mnCl_4]^{2-}$ iii. $[Ni(CN)_4]^{2-}$ iv. $Ni(CO)_4$
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Answer: A —
i and iii
$[PdCl_4]^{2-}$ and $[Ni(CN)_4]^{2-}$ are square planar complexes.
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16.
Predict the correct order of isoelectronic species
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Answer: A —
$N^{3-} > O^{2-} > F^- > Na^+$
For isoelectronic species, ionic radius decreases as nuclear charge (Z) increases.
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17.
Which statement/s is correct regarding the inert pair effect ? i. The increased stability of $Tl^+$ compared to $Tl^{3+}$ . ii. Favours a lower oxidation state in heavier p-block elements. iii. Favours a higher oxidation state in heavier p-block elements. iv. down the group, poor shielding effect by intervening d and f electrons.
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Answer: B —
i, ii, iv
The inert pair effect stabilizes the lower oxidation state due to poor shielding of s-electrons by d and f orbitals.
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18.
Which of the following electronic conﬁgurations exhibits Jahn-Teller distortions in an octahedral ﬁeld ?
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Answer: A —
$d^1, d^2, d^4$
Jahn-Teller distortion is most pronounced in high-spin $d^4$ , low-spin $d^7$ , and $d^9$ configurations.
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19.
Which of the following is a Pt-based anticancer drug ?
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Answer: A —
Cisplatin
Cisplatin is a well-known platinum-based chemotherapy drug.
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20.
Choose the incorrect statements from the following. i. Ionisation energy is inversely proportional to atomic radius. ii. The ionisation energy of an atom may be negative. iii. The ionisation energy of an atom may be positive. iv. Ionisation energy is the amount of energy required to remove an electron from the outermost shell of an isolated gaseous atom.
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Answer: B —
i, iii, iv
Ionization energy is always positive (endothermic process).
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21.
Find the most stable one among the following cations.
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Answer: B —
Tertiary butyl cation
Tertiary carbocations are the most stable due to inductive effect and hyperconjugation.
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22.
Which among the following rotate plane polarized light ? i. Enantiomers ii. diastereomers iii. mesomers
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Answer: A —
i and ii
Enantiomers and diastereomers are optically active and rotate plane-polarized light.
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23.
Find the wrong statement.
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Answer: D —
Trans isomers have low melting point
Trans isomers generally have higher melting points due to better symmetry and packing.
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24.
Boat form of cyclohexane is less stable than the chair form mainly because of repulsion between hydrogens at 1, 4 positions named
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Answer: C —
Flagpole hydrogens
The instability of the boat form is due to steric repulsion between the flagpole hydrogens.
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25.
In Bimolecular nucleophilic substitution ( $S_N2$ ), there occurs
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Answer: B —
Complete inversion of conﬁguration
$S_N2$ reactions proceed via a backside attack, resulting in Walden inversion.
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26.
Which among the following are aromatic ? i. Tropylium cation ii. Cyclopentadienyl cation iii. Cyclopentadienly anion
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Answer: B —
i and iii
Tropylium cation (6 pi electrons) and cyclopentadienyl anion (6 pi electrons) are aromatic.
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27.
The phenomenon in which enrichment of waterbodies by nitrates and phosphates leading to Algal bloom
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Answer: D —
Eutrophication
Eutrophication is the process where nutrient enrichment leads to excessive plant and algal growth.
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28.
Among the following, the most toxic form of mercury is
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Answer: C —
methyl mercury
Methyl mercury is highly toxic and bioaccumulates in the food chain.
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29.
drugs used to reduce body temperature is called
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Answer: A —
Antipyretics
Antipyretics are medications that lower body temperature.
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30.
In petroleum reﬁning which puriﬁcation technique is widely used ?
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Answer: C —
Fractional distillation
Fractional distillation is the standard method for separating components of crude oil based on boiling points.
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31.
Identify the reagent used in Wittig reaction.
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Answer: C —
Phosphonium ylide
The Wittig reaction involves the reaction of an aldehyde or ketone with a phosphonium ylide.
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32.
The major products of Fries rearrangement is formed at _______ positions.
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Answer: A —
Ortho and Para Positions
Fries rearrangement of phenolic esters typically yields ortho and para-hydroxy ketones.
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33.
Identify the product and name of the reaction.
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Answer: D —
C6H5COCH2CH2N(CH3)2, mannich Reaction
The Mannich reaction involves the condensation of a ketone with formaldehyde and an amine to form a beta-amino ketone.
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34.
The total number of π electrons in naphthalene is
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Answer: C —
10
Naphthalene consists of two fused benzene rings, containing 10 π electrons.
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35.
Gabriel phthalimide synthesis is mainly used for the preparation of
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Answer: B —
Primary Amines
Gabriel phthalimide synthesis is a standard method for the synthesis of primary aliphatic amines.
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36.
Phenol is more acidic than ethanol because
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Answer: C —
Phenoxide ion is resonance stabilized
The phenoxide ion formed after deprotonation is stabilized by resonance with the aromatic ring, making phenol more acidic.
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37.
Which catalyst is commonly used in the Friedel-Crafts alkylation reaction ?
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Answer: B —
AlCl3
Anhydrous aluminum chloride ( $AlCl_3$ ) is the most common Lewis acid catalyst used in Friedel-Crafts alkylation.
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38.
Which one of the compounds is the epimer of glucose ?
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Answer: A —
mannose
Mannose is the C-2 epimer of glucose.
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39.
mutarotation proves that glucose exists predominantly in
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Answer: C —
Cyclic hemiacetal form
Mutarotation is the change in optical rotation due to the interconversion of alpha and beta anomers in the cyclic hemiacetal form.
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40.
The starting materials for the preparation of PETP are
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Answer: B —
Ethylene Glycol and Terephthalic Acid
Polyethylene terephthalate (PETP) is synthesized from ethylene glycol and terephthalic acid.
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41.
What is the ratio of root mean square velocities of $H_2$ at 200 K and that of $O_2$ at 800 K ?
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Answer: B —
2
$v_{rms} = \sqrt{\frac{3RT}{M}}$ . For $H_2$ (M=2) at 200K: $\sqrt{\frac{3R(200)}{2}} = \sqrt{300R}$ . For $O_2$ (M=32) at 800K: $\sqrt{\frac{3R(800)}{32}} = \sqrt{\frac{2400R}{32}} = \sqrt{75R}$ . Ratio is $\sqrt{\frac{300}{75}} = \sqrt{4} = 2$ . Wait, checking calculation: $H_2$ at 200K is $\sqrt{300R}$ , $O_2$ at 800K is $\sqrt{75R}$ . Ratio is 2.
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42.
For a certain crystal, the unit cell lengths are all different and the unit cell angles are all perpendicular. Which crystal system does it belong to ?
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Answer: D —
Orthorhombic
In an orthorhombic system, $a \neq b \neq c$ and $\alpha = \beta = \gamma = 90^\circ$ .
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43.
Which of the following is expected to be a p-type semiconductor ?
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Answer: A —
AI doped Si
Doping with group 13 elements (like Al) creates electron holes, resulting in p-type semiconductors.
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44.
Which of the following spectroscopic techniques make use of absorption of infrared radiation by the molecules ?
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Answer: C —
Vibrational spectroscopy
Vibrational spectroscopy (IR spectroscopy) involves the absorption of infrared radiation to excite molecular vibrations.
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45.
If the volume of the system remains constant in a thermodynamic process, it is called an
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Answer: A —
Isochoric process
An isochoric process is a thermodynamic process that occurs at constant volume.
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46.
Consider the complete combustion reaction of liquid benzene to gaseous $CO_2$ and gaseous $H_2O$ as products. The sign of $\Delta S$ and $\Delta G$ of this reaction would be
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Answer: B —
positive $\Delta S$ , negative $\Delta G$
Combustion is a spontaneous process ( $\Delta G < 0$ ) and increases the number of moles of gas, leading to an increase in entropy ( $\Delta S > 0$ ).
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47.
Which of the following reactions is expected to have the lowest heat of neutralisation ?
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Answer: A —
$CH_3COOH$ and $NH_4OH$
The heat of neutralization is lowest for weak acid-weak base reactions because energy is consumed in the dissociation of the weak acid and weak base.
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48.
For the reaction, $2N_2O(g) + N_2H_4(g) \rightleftharpoons 3N_2(g) + 2H_2O(g)$ , $K_p/K_c$ is
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Answer: C —
$(RT)^2$
$K_p = K_c(RT)^{\Delta n}$ . Here $\Delta n = (3+2) - (2+1) = 5 - 3 = 2$ . Wait, $2N_2O + N_2H_4 \rightarrow 3N_2 + 2H_2O$ . $\Delta n = 5 - 3 = 2$ . So $K_p/K_c = (RT)^2$ . Let me re-check the stoichiometry. $2N_2O + N_2H_4 \rightarrow 3N_2 + 2H_2O$ . $\Delta n = 5 - 3 = 2$ . The answer key says A (1). Perhaps the reaction is $N_2O + N_2H_4 \rightarrow 2N_2 + H_2O$ ? No, the text says $2N_2O + N_2H_4 \rightarrow 3N_2 + 2H_2O$ . If $\Delta n = 0$ , then $K_p/K_c = 1$ . Let's re-count: $2N_2O + N_2H_4$ (3 moles gas) $\rightarrow 3N_2 + 2H_2O$ (5 moles gas). $\Delta n = 2$ . The key might be based on a different equation.
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49.
When a solid compound AB (s) melts at a particular temperature into liquid AB (l), without undergoing decomposition, it is said to be
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Answer: D —
Congruent melting
Congruent melting occurs when a solid melts to form a liquid of the same composition.
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50.
What structure is the unit cell of NaCl ?
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Answer: B —
Face centered cubic
NaCl crystallizes in a face-centered cubic (fcc) lattice structure.
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51.
The pH of 0.0001 m HCl is
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Answer: A —
4
$pH = -\log[H^+] = -\log(10^{-4}) = 4$ .
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52.
Ostwald’s dilution law is applicable to
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Answer: B —
Weak electrolytes only
Ostwald's dilution law describes the dissociation of weak electrolytes.
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53.
Which of the following is false ?
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Answer: D —
Order of a reaction can be whole numbers only
The order of a reaction can be zero, fractional, or an integer, not just whole numbers.
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54.
Unit of zero order rate constant is
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Answer: B —
$mol dm^{-3}s^{-1}$
For a zero-order reaction, the rate constant has the same units as the rate, which is concentration per unit time ( $mol dm^{-3} s^{-1}$ ).
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55.
A hypertonic solution has
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Answer: A —
Higher osmotic pressure than another solution
A hypertonic solution has a higher solute concentration and thus a higher osmotic pressure than the reference solution.
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56.
If the transference number of an anion is 0.7, the transference number of the cation is
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Answer: B —
0.3
The sum of transference numbers of cation and anion is 1. $1 - 0.7 = 0.3$ .
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57.
An example of Oxidation-Reduction electrode is
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Answer: C —
Quinhydrone electrode
The quinhydrone electrode is a redox electrode consisting of an inert platinum wire in a solution of quinhydrone.
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58.
Identify the point group of Ammonia molecule.
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Answer: C —
$C_{3V}$
Ammonia ( $NH_3$ ) has a trigonal pyramidal geometry, which belongs to the $C_{3v}$ point group.
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59.
In Jablonski diagram, identify the transition that involve a change in spin multiplicity.
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Answer: B —
Intersystem crossing
Intersystem crossing is a non-radiative transition between states with different spin multiplicities (e.g., singlet to triplet).
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60.
Which is the quantum mechanical operator for momentum ?
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Answer: C —
$\frac{h}{2\pi i} \nabla$
The momentum operator in one dimension is $\hat{p}_x = -i\hbar \frac{\partial}{\partial x} = \frac{h}{2\pi i} \frac{\partial}{\partial x}$ .
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61.
Corrosion resistance of stainless steel is due to
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Answer: D —
Formation of $FeCr_2O_4$
Stainless steel resists corrosion due to the formation of a passive chromium oxide layer ( $Cr_2O_3$ ) on the surface.
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62.
Which among the following is/are incorrect in Bayer process for the beneficiation of aluminium from bauxite ? i. differences in basic properties of metal ions are exploited. ii. AI $_2$ O $_3$ is converted into [AI(OH) $_4$ ] $^-$ . iii. Hydroxo anions of AI are heated to yield AI(OH) $_3$ .
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Answer: B —
Only i and iii
In the Bayer process, $Al_2O_3$ is dissolved in NaOH to form $[Al(OH)_4]^-$ . The precipitation step involves seeding with $Al(OH)_3$ to recover $Al(OH)_3$ , not heating the anions.
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63.
Which among the following is/are correct about carbon allotropes ? i. Graphite is more reactive than diamond . ii. Conversion of diamond to graphite is thermodynamically favoured . iii. Hybridization of carbon in fullerene is between sp $^2$ and sp $^3$ . iv. At NTP stable phase of carbon is graphite.
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Answer: D —
All of the above
All statements are correct: Graphite is more reactive, diamond to graphite conversion is spontaneous (though slow), fullerenes have intermediate hybridization, and graphite is the stable allotrope at NTP.
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64.
The metal ions present in carboxy peptidase and carbonic anhydrase are
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Answer: D —
Zn and Zn only
Both carboxypeptidase and carbonic anhydrase are zinc-containing metalloenzymes.
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65.
Identify the catalyst that converts synthesis gas into hydrocarbons.
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Answer: B —
Fischer Tropsch catalyst
The Fischer-Tropsch process uses catalysts (typically Fe or Co) to convert synthesis gas ( $CO + H_2$ ) into liquid hydrocarbons.
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66.
Identify the compound that is not principally present in dry cement.
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Answer: C —
Ca $_2$ (Si $_4$ O $_{10}$ )
Portland cement primarily consists of $Ca_3SiO_5$ (alite), $Ca_2SiO_4$ (belite), $Ca_3Al_2O_6$ , and $Ca_4Al_2Fe_2O_{10}$ . $Ca_2(Si_4O_{10})$ is not a primary component.
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67.
Which of the following is correct about the bandgaps of semiconductors ?
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Answer: C —
GaN > GaAs > Si > Ge
The bandgaps are approximately: GaN (~3.4 eV), GaAs (~1.4 eV), Si (~1.1 eV), and Ge (~0.67 eV).
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68.
Which among the following is not in accordance with lyotropic series ?
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Answer: D —
CIO $_3^-$ > NO $_3^-$
The lyotropic series for cations is generally $Mg^{2+} > Ca^{2+} > Sr^{2+} > Ba^{2+}$ . The order $Ca^{2+} > Ba^{2+}$ is consistent, but the question asks for what is NOT in accordance. Based on standard series, $Na^+ > K^+$ is correct, but $Ca^{2+} > Ba^{2+}$ is also correct. Re-evaluating, the series for anions is $SO_4^{2-} > Cl^- > NO_3^- > ClO_3^-$ . Thus, $ClO_3^- > NO_3^-$ is incorrect.
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69.
Which of the following statements is/are incorrect about carbon nanotubes ? i. If zigzag edges are joined, the end carbon atoms will have a chair arrangement. ii. If armchair edges are joined, the end carbon atoms will have a zigzag arrangement. iii. If different rows are joined, the nanotube formed will be chiral.
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Answer: D —
None of the above
All statements are correct descriptions of the geometry of carbon nanotubes based on how the graphene sheet is rolled.
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70.
Which among the following statements is/are not true about zeolites ? i. They have the ability to hydrate and dehydrate reversibly ii. They have the ability to exchange their constituent cations iii. They have both Bronsted and lewis acid sites iv. Primary building units are Si and AI containing tetrahedron
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Answer: C —
None of the above
All four statements are true characteristics of zeolites.
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71.
The major product formed on sulfonating aniline is
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Answer: B —
🔍 Click to zoom
Sulfonation of aniline produces sulfanilic acid (p-aminobenzenesulfonic acid).
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72.
Which among the following is an incorrect statement about phthalic anhydride ?
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Answer: C —
Its preparation is done industrially from phthalic acid
Phthalic anhydride is produced industrially by the catalytic oxidation of o-xylene or naphthalene, not from phthalic acid.
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73.
Which among these polymer processing methods does not require additional pressure ?
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Answer: A —
Casting
Casting involves pouring a liquid monomer or polymer into a mold and allowing it to harden without the application of external pressure.
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74.
The correct order of steps to obtain an elastomer of desired shape and property is
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Answer: C —
mastication, compounding, molding, vulcanization
The standard processing sequence for rubber is mastication (softening), compounding (adding ingredients), molding (shaping), and vulcanization (cross-linking).
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75.
High purity ethanol is obtained by
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Answer: D —
Rectification distillation
Rectification (or fractional distillation with a column) is used to obtain high-purity ethanol.
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76.
Which among the following is not related to the drying efficiency of a product ?
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Answer: D —
Specific conductivity
Drying efficiency depends on heat transfer (specific heat), mass transfer (diffusivity), and the nature of the substance (molecular weight), but not typically on specific conductivity.
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77.
Which of the following is a banned/restricted chemical ?
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Answer: C —
Acetic anhydride
Acetic anhydride is a controlled substance under the Narcotic Drugs and Psychotropic Substances Act due to its use in the illicit manufacture of heroin.
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78.
Which of the following is industrially prepared using esterification process ?
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Answer: B —
dioctyl phthalate
Dioctyl phthalate (DOP) is a plasticizer produced by the esterification of phthalic anhydride with 2-ethylhexanol.
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79.
Which of the following will not be a product when benzoyl chloride is hydrogenated in presence of palladium ? (NB : catalyst is not poisoned)
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Answer: A —
Benzoic acid
Rosenmund reduction of benzoyl chloride yields benzaldehyde. Further hydrogenation can lead to benzyl alcohol and toluene. Benzoic acid is not a product of this hydrogenation.
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80.
Identify the thermometer which works based on change in resistivity on heating.
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Answer: C —
digital thermometer
Digital thermometers often use thermistors or RTDs, which operate based on the change in electrical resistance with temperature.
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81.
Which processing method is best for production of thermally insulating and lightweight packaging materials ?
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Answer: B —
Foaming
Foaming processes (like expanded polystyrene) are used to create lightweight, insulating materials.
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82.
A rubber manufacture uses peroxide curing instead of sulfur curing. Which property is most likely to be improved ?
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Answer: D —
High temperature stability
Peroxide-cured rubbers form carbon-carbon crosslinks, which provide superior thermal stability compared to the sulfur-sulfur bonds in sulfur curing.
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83.
Identify the ﬁlter that uses backwashing to restore its ﬁltration efﬁciency.
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Answer: A —
Sand ﬁlter
Sand filters are commonly cleaned by reversing the flow of water (backwashing) to remove accumulated solids.
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84.
In vacuum distillation, reducing the system pressure leads to
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Answer: C —
The vapor pressure matches the reduced external pressure
Distillation occurs when the vapor pressure of the liquid equals the external pressure; reducing external pressure allows boiling at lower temperatures.
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85.
The para product predominates over the ortho product during chlorobenzene nitration mostly due to
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Answer: A —
Reduced steric crowding in the para position
The para position is less sterically hindered than the ortho position, making it the preferred site for electrophilic substitution.
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86.
Oxidation of which aromatic derivative results in isophthalic acid ?
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Answer: C —
meta-Xylene
Oxidation of meta-xylene yields isophthalic acid (benzene-1,3-dicarboxylic acid).
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87.
Electrophilic aromatic sulphonation proceeds through the formation of ___________, in contrast to Fischer esteriﬁcation.
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Answer: A —
Arenium ion
Electrophilic aromatic substitution involves the formation of a sigma complex or arenium ion intermediate.
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88.
The fundamental cleaning agent in the majority of domestic detergents is
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Answer: D —
Sodium alkylbenzene sulfonate
Sodium alkylbenzene sulfonates are the most common surfactants used in synthetic detergents.
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89.
The concentration of a suspension increases while the particle size remains the constant. Which device would produce the highest measured signal ?
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Answer: B —
Nephelometer
A nephelometer measures turbidity by detecting light scattered by particles in a suspension; signal increases with concentration.
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90.
Which thermal property is detected by dSC but not directly by TGA ?
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Answer: D —
Glass transition
DSC measures heat flow associated with transitions like glass transition, which does not involve a mass change detectable by TGA.
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91.
Which fraction of crude oil is mainly used as aviation turbine fuel ?
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Answer: C —
Kerosene
Kerosene-type fractions are the primary components used for aviation turbine fuel (Jet A/A-1).
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92.
Which of the following statements regarding fractional distillation are correct ? 1. Separation is based on differences in boiling points. 2. Gasoline is obtained before kerosene. 3. Asphalt is collected from the top of the distillation column. 4. LPG is one of the ﬁrst products to leave the column.
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Answer: B —
Only 1, 2 and 4
Asphalt is a heavy residue collected from the bottom, not the top. Statements 1, 2, and 4 are correct.
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93.
Which of the following statements regarding petroleum sweetening are correct ? 1. Sweetening removes objectionable sulfur compounds. 2. The doctor’s process converts mercaptans into disulﬁdes. 3. The copper chloride process is a sweetening process. 4. Sweetening increases the caloriﬁc value of petroleum products.
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Answer: C —
Only 1, 2 and 3
Sweetening converts mercaptans to less odorous disulfides but does not significantly change the calorific value.
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94.
The working principle of magneto-hydrodynamics power generators is based on
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Answer: D —
Faraday’s law of Electromagnetic Induction
MHD generators work by moving a conducting fluid through a magnetic field, inducing an electric current based on Faraday's law.
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95.
Which of the following statements about nuclear reactors are correct ? 1. Control rods regulate the rate of ﬁssion. 2. A moderator slows down fast neutrons. 3. Uranium-238 is a commonly used isotope as nuclear fuel. 4. The coolant is used to absorb excess neutrons.
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Answer: C —
Only 1 and 2
Control rods absorb neutrons to regulate fission, and moderators slow neutrons. Uranium-235 is the primary fuel, not U-238.
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96.
Which calorimeter is used for gaseous fuels ?
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Answer: A —
Junker’s gas calorimeter
Junker's calorimeter is specifically designed to measure the calorific value of gaseous fuels.
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97.
Proximate analysis of coal does not determine
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Answer: D —
Carbon percentage
Proximate analysis determines moisture, volatile matter, ash, and fixed carbon. Ultimate analysis determines elemental composition like carbon percentage.
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98.
Rotary kilns are widely used in
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Answer: A —
Cement manufacture
Rotary kilns are the standard equipment used in the production of cement clinker.
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99.
Which of the following statements regarding ﬂuidized bed combustion are correct ? 1. It provides efﬁcient mixing of fuel and air. 2. It reduces SO 2 emissions by adding limestone. 3. It operates at relatively lower temperatures than conventional furnaces. 4. It produces more NO x than pulverized coal combustion.
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Answer: B —
Only 1, 2 and 3
Fluidized bed combustion operates at lower temperatures, reducing NOx emissions compared to conventional furnaces.
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100.
The efﬁciency of OTEC power generation depends primarily on
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Answer: D —
Temperature difference between surface and deep seawater
Ocean Thermal Energy Conversion (OTEC) utilizes the temperature gradient between warm surface water and cold deep water to run a heat engine.
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