Subject Specialist SS Chemistry Solved MCQs Past Papers

Chemistry MCQs

(2) If the rate of a reaction does not change with time then the reaction should be:
(a) moderately slow (b) very fast (c) catalyzed
(d) zeroth order (e) None of these.

(3) If a chemical reaction reaches equilibrium state:
(a) its forward and backward rates are equal
(b) its overall free energy change becomes zero
(c) its equilibrium constant is the ratio of the two rate constants
(d) all of these (e) none of these

(4) PCl5(g) ® PCl3(g) +Cl2(g). The units of equilibrium constant, Kc for the reaction
(a) L mol–1 (b) mol L –1 (c) mol –1 L –1
(d) mol –2 L–2 (e) None of these

Test Preparation Material

(5) Energy of a typical H – bond ranges between:
(a) 2 to 4 kJmol –1 (b) 5 to 10 kJmol –1
(c) 15 to 30 kJmol –1 (d) 40 to 80 kJmol –1
(e) None of these

(6) Which of the pairs makes an “ideal mixture”:
(a) benzene-methanol (b) benzene-toluene
(c) ethanol-methanol (d) ethanol-water
(e) None of these

(7) Which of the following concentration units depends on temperature?
(a) molarity (b) molality
(c) mole fraction (d) weight to weight (W/W) %
(e) None of these

(8) A 0.4% (W/V) aqueous solution of NaOH is nearly:
(a) 1 M (b) 0.5 M (c) 0.1 M
(d) 0.01 M (e) None of these

(9) Which of the followings is correct for the ground state of O2 molecule?
(a) bond order two and no unpaired electron
(b) bond order two and one unpaired electron
(c) bond order two and two unpaired electron in the bonding orbital
(d) bond order two and two unpaired electrons in the anti-bonding orbital
(e) None of these

(10) Which one should give the simplest proton NMR spectrum?
(a) CH3CH2OH (b) CH3OH (c) CH3OCH3
(d) CH3CHO (e) all are equally complicated

(11) Which group has the highest stretching frequency of IR-region in the gas phase?
(a) º C -H (b) = C -H (c) – O – H
(d) – N – H (e) all are equal

(12) Which of the following should not be formed according to the bonding theories?
(a) H +
2 (b) H –
2 (c) He 2
(d) He2
+ (e) None of these

(13) There remains no liquid-vapour boundary at:
(a) boiling point (b) critical temperature
(c) triple point (d) azeotrope composition
(e) None of these

(14) For a catalyzed reaction as compared to the uncatalyzed one:
(a) heat of reaction is higher (b) heat of reaction is lower
(c) heat of reaction is same (d) activation energy is same
(e) All above are correct

(15) When two ideal gases at the same temperature are mixed together:
(a) there is a negative heat of mixing
(b) there is a positive heat of mixing
(c) both heat and entropy of mixing are positive
(d) entropy of mixing alone is positive
(e) All above are correct

(16) Which of the series is present in the ultraviolet region for the H – atom?
(a) Layman (b) Balmer (c) Paschen
(d) Pfund (e) None of these

(17) pH of 0.01 M HCl solution should be:
(a) 3 (b)2 (c)1.5
(d) 1 (e) None of these

(18) Which of the ions should exhibit highest electrical mobility in aqueous solution?

(a) Na+ (b) I (c) Cs+
(d) Cd++ (e) Li+

(19) H2 + Br2 ® 2HBr is a very famous gas phase reaction. The overall order of this
reaction is:
(a) two (b) one (c) half
(d) one half in the beginning (e) All above are correct

(20) Presence of a chiral center in molecules makes them:
(a) absorb uv–radiation (b) absorb plane polarized light
(c) rotate plane polarized light (d) emit IR–radiation
(e) None of these

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