Chemistry MCQs for PPSC Lecturer Test Preparation

1). Compound in which carbons use only sp3 hybrid orbitals for bond formation is:

(a). CH3CH2CH3

(b). CH3C≡CH

(c). CH3CH=CH2

(d). CH2=CH—CH=CH2

2). When the carbon atom is sp2 hybridized in a compound, it is bonded to:

(a). 2 other atoms

(b). 4 other atoms

(c). 3 other atoms

(d). 5 other atoms

3). Which of the following is a planar molecule?

(a). Formaldehyde

(b). Acetone

(c). Formic acid

(d). Acetic acid

4). What is bond angle between the hybrid orbitals in methane?

(a). 180°

(b). 120°

(c). 109.5°

(d). 115.5°

5). The H–C–C bond angle in ethane is:

(a). 60°

(b). 109.5°

(c). 120°

(d). 118°28′

6). The H–C–H bond angle in ethylene is:

(a). 60°

(b). 120°

(c). 90°

(d). 180°

7). What is the bond length of a carbon-carbon double bond?

(a). 1.20 Å

(b). 1.34 Å

(c). 1.54 Å

(d). 1.68 Å

8). The carbon-carbon bond lengths in rank of increasing bond length is:

(a). triple, double, single

(b). single, double, triple

(c). single, triple, double

(d). triple, single, double

9). Which of the following is the correct order of bond lengths:

(a). C–C < C=C < C≡C

(b). C–C > C≡C > C=C

(c). C≡C > C–C > C=C

(d). C≡C < C–C > C=C

10). How many atoms are attached to an atom having a sp hybridization?

(a). 0

(b). 1

(c). 2

(d). 3

11). How many optical isomers are possible for lactic acid?

(a). 2

(b). 4

(c). 6

(d). 8

12). Which of the following represents a racemic mixture?

(a). 75% (R)-2-butanol, 25% (S)-2-butanol

(b). 25% (R)-2-butanol, 75% (S)-2-butanol

(c). 50% (R)-2-butanol, 50% (S)-2-butanol

(d). None of the above

13). Consider (R)- and (S)-2-butanol. Which physical property distinguishes the two compounds?

(a). melting point

(b). solubility in common solvents

(c). Rotation of plane-polarized light

(d). Infrared spectrum

14). Which of the following is capable of exhibiting cis-trans isomerism?

(a). 1-butene

(b). 1-pentene

(c). ethene

(d). 2-butene

15). Which of the following is a true statement?

(a). All chiral molecules possess a plane of symmetry.

(b). All achiral molecules are meso.

(c). All molecules which possess a single asymmetric center of the S configuration are levorotatory.

(d). A mixture of achiral compounds will be optically inactive.

16). Which of the statements below correctly describes an achiral molecule?

(a). The molecule has a nonsuperimposable mirror image.

(b). The molecule exhibits optical activity when it interacts with plane-polarized

light.

(c). The molecule has an enantiomer.

(d). The molecule might be a meso form.

17). How many asymmetric centers are present in a molecule of 2,4,6- trimethylheptane?

(a). 0

(b). 1

(c). 2

(d). 3

18). Which of the following compounds is never chiral?

(a). 2,3-dibromobutane

(b). 1,3-dibromobutane

(c). 1,2-dichlorobutane

(d). 1,4-dibromobutane

19). Which of the following statements is correct concerning a pair of enantiomers?

(a). They rotate the plane of polarized light by exactly the same amount and in

opposite directions.

(b). They rotate the plane of polarized light by differing amounts and

in opposite directions.

(c). They rotate the plane of polarized light by differing amounts and in the same

direction.

(d). They have different melting points.

20). Which of the following is not true of enantiomers?

(a). They have the same melting point.

(b). They have the same boiling point.

(c). They have the same density.

(d). They have the same specific rotation.

21). A and B are stereoisomers. They are nonsuperimposable and are mirror images of one another. Which of the following best describes the relationship between A and B?

(a). structural isomers

(b). enantiomers

(c). cis-trans isomers

(d). diastereomers

22). Which of the statements is correct about diastereomers?

(a). They are stereoisomers that are not enantiomers.

(b). They are a pair of identical isomers.

(c). They are a pair of isomers that are mirror images.

(d). All their asymmetric centers are the same.

23). Which of the following is/are optically inactive?

(a). a 50-50 mixture of R and S enantiomers

(b). a meso compound

(c). a racemic mixture

(d). all the above

24). Hydrocarbons are:

(a). Composed of carbon and hydrogen

(b). Composed of carbon, hydrogen, and oxygen

(c). Composed of carbon and oxygen

(d). Composed of carbon and nitrogen

25). 2-Methylpropene reacts with HBr to give:

(a). tert-Butyl bromide

(b). Isobutane

(c). n-Butyl bromide

(d). None of these

26). 2-Butene reacts with HBr to give:

(a). 1-Bromobutane

(b). 2,3-Dibromobutane

(c). 2-Bromobutane

(d). 2,2-Dibromobutane

27). Which of the following alkenes reacts with HBr in the presence of a peroxide to give anti-Markovnikov’s product?

(a). 1-Butene

(b). 2,3-Dimethyl-2-butene

(c). 2-Butene

(d). 3-Hexene

28). Propene reacts with HBr in the presence of a peroxide to give:

(a). n-Propyl bromide

(b). Allyl bromide

(c). Isopropyl bromide

(d). Vinyl bromide

29). 2-Methylpropene reacts with HBr in the presence of peroxide to give:

(a). A primary alkyl bromide

(b). A secondary alkyl bromide

(c). A tertiary alkyl bromide

(d). A vicinal dibromide

30). 2-Methyl-2-butene reacts with HBr in the presence of peroxide to give:

(a). A primary alkyl bromide

(b). A secondary alkyl bromide

(c). A tertiary alkyl bromide

(d). A vicinal dibromide

31). Hydration of 2-methyl-1-propene (with H2O/H2SO4) gives:

(a). CH3CH2CH2OH

(b). (CH3)3COH

(c). CH3CH2CH2CH2OH

(d). (CH3)2CHOH

32). A compound reacts with steam in the presence of concentrated H2SO4 to give isopropyl alcohol. The compound could be:

(a). Alkane

(b). Alkyne

(c). Alkene

(d). Allene

33). Propene reacts with Cl2 in H2O to give:

(a). 1-Chloro-2-propanol

(b). 2-Chloro-2-propanol

(c). 1-Chloro-1-propanol

(d). 2-Chloro-1-propanol

34). 1-Butene reacts with Cl2 in H2O to give:

(a). 1-Chloro-2-butanol

(b). 2-Chloro-2-butanol

(c). 1-Chloro-1-butanol

(d). 2-Chloro-1-butanol

35). Catalytic hydrogenation of 3-methyl-1-butene gives:

(a). Isobutane

(b). 2,2-Dimethylbutane

(c). 2-Methylbutane

(d). 2,3-Dimethylbutane

36). Which of the following alkenes gives only acetic acid on oxidation with hot concentrated KMnO4.

(a). Ethylene

(b). 1-Butene

(c). Propene

(d). 2-Butene

37). n-Propyl iodide reacts with sodium ethoxide to give:

(a). CH3CH2OCH2CH3

(b). CH3CH2OCH2CH2CH3

(c). CH3CH2OCH3

(d). CH3OCH2CH2CH3

38). 1-Bromobutane reacts with alcoholic KOH to mainly give:

(a). 1-Butene

(b). 2-Butene

(c). 1-Butanol

(d). 2-Butanol

39). 2-Bromobutane reacts alcoholic KOH to mainly give:

(a). 1-Butene

(b). 2-Butene

(c). 1-Butanol

(d). 2-Butanol

40). Isopropyl bromide reacts with alcoholic KOH to give:

(a). Propene

(b). Isopropyl alcohol

(c). Propane

(d). n-Propyl alcohol

41). 2,2-Dichloropropane reacts with aqueous KOH to give:

(a). 2,2-Propanediol

(b). Propanal

(c). Acetone

(d). Propene

42). 1,1-Dichloropropane reacts with aqueous KOH to give:

(a). 1,1-Propanediol

(b). Acetaldehyde

(c). Propanone

(d). Propyne

43). Which of the following compounds will not give a white precipitate with

alcoholic AgNO3.

(a). Bromobenzene

(b). 1-Bromopropane

(c). Ethyl bromide

(d). 2-Bromopropane

44). Which of the following compounds will give a white precipitate with alcoholic AgNO3?

(a). Vinylbenzene

(b). Chlorobenzene

(c). Vinyl chloride

(d). Allyl chloride

45). Carbylamine test involves heating a mixture of

(a). alcoholic KOH, methyl iodide, and sodium metal

(b). alcoholic KOH, methyl iodide, and primary amine

(c). alcoholic KOH, chloroform, and primary amine

(d). alcoholic KOH, methyl alcohol, and primary amine

46). When chloroform is heated with aqueous NaOH, it gives

(a). Formic acid

(b). Sodium formate

(c). Acetic acid

(d). Sodium acetate

47). Which of the following reagents can be used to oxidize 1° alcohols to aldehydes?

(a). KMnO4

(b). MnO2

(c). K2Cr2O7

(d). PCC

  1. What is the major product from the acid-catalyzed hydration of 2-methyl-2- pentene?

(a). 2-methylpentane

(b). 2-methyl-1-pentanol

(c). 2-methyl-2-pentanol

(d). 2-methyl-3-pentanol

49). In cold countries ethylene glycol is added to water in car radiators. This helps to:

(a). Reduce the viscosity

(b). Make water a better lubricant

(c). Lower the freezing point

(d). Lower the boiling point

50). Ethylene oxide undergoes acid-hydrolysis to form

(a). Ethylene glycol

(b). Formic acid

(c). Ethyl alcohol

(d). Acetic acid

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