Haloalkanes and Haloarenes Chapter-Wise Test 12

Correct answer Carries: 4.

Wrong Answer Carries: -1.

What is the product when \( \ce{CH3CH2CH2CH2OH} \) reacts with \( \ce{PBr3} \)?

\( \ce{PBr3} \) converts 1-butanol (\( \ce{CH3CH2CH2CH2OH} \)) to 1-bromobutane (\( \ce{CH3CH2CH2CH2Br} \)) by replacing \( \ce{OH} \) with Br.

\( \ce{CH3CH2CH3} \)
\( \ce{CH3CH2CH=CH2} \)
\( \ce{CH3CH2CH2CH2Br} \)
\( \ce{CH3CHBrCH2CH3} \)
3

Which of the following gives a white precipitate with \( \ce{AgNO3} \) instantly?

Tertiary halides like \( \ce{(CH3)3CCl} \) ionize readily via \( \ce{S_N1} \), forming \( \ce{AgCl} \) precipitate instantly with \( \ce{AgNO3} \).

\( \ce{CH3Cl} \)
\( \ce{CH3CH2Cl} \)
\( \ce{CH3CHClCH3} \)
\( \ce{(CH3)3CCl} \)
4

What is the product when \( \ce{(CH3)2CHCH2CH2Br} \) reacts with alcoholic \( \ce{KOH} \) at low temperature?

Elimination (E2) of \( \ce{(CH3)2CHCH2CH2Br} \) with alcoholic \( \ce{KOH} \) forms \( \ce{(CH3)2C=CHCH3} \) (2-methyl-2-butene) per Zaitsev’s rule.

\( \ce{(CH3)2CHCH2CH2OH} \)
\( \ce{CH3CH2CH=CHCH3} \)
\( \ce{(CH3)2CHCH=CH2} \)
\( \ce{(CH3)2C=CHCH3} \)
4

What is the order of boiling points of \( \ce{CH3Cl} \), \( \ce{CH3Br} \), and \( \ce{CH3I} \)?

Boiling points increase with molecular weight due to stronger London forces. The order is \( \ce{CH3I} \) (highest) > \( \ce{CH3Br} \) > \( \ce{CH3Cl} \).

\( \ce{CH3Cl} \) > \( \ce{CH3Br} \) > \( \ce{CH3I} \)
\( \ce{CH3Br} \) > \( \ce{CH3I} \) > \( \ce{CH3Cl} \)
\( \ce{CH3I} \) > \( \ce{CH3Br} \) > \( \ce{CH3Cl} \)
\( \ce{CH3Cl} \) > \( \ce{CH3I} \) > \( \ce{CH3Br} \)
3

Which halide is a vinylic halide?

A vinylic halide has the halogen on a carbon of a C=C bond. \( \ce{CH3CH=CHBr} \) (1-bromopropene) is vinylic.

\( \ce{CH3CH2CH2Br} \)
\( \ce{C6H5CH2Br} \)
\( \ce{CH3CH2CH=CH2} \)
\( \ce{CH3CH=CHBr} \)
4

Which of the following is a geminal dihalide?

A geminal dihalide has two halogens on the same carbon. \( \ce{CH3CH2CCl2CH3} \) (2,2-dichlorobutane) is geminal.

\( \ce{CH3CHClCH2Cl} \)
\( \ce{CH2ClCH2CH2Cl} \)
\( \ce{CH3CH2CCl2CH3} \)
\( \ce{CH3CHClCHClCH3} \)
3

Which halide is an allylic halide?

An allylic halide has the halogen on a carbon adjacent to a C=C bond. \( \ce{CH2=CHCH2Br} \) (3-bromopropene) is an allylic halide.

\( \ce{CH3CH2Br} \)
\( \ce{CH2=CHCl} \)
\( \ce{C6H5CH2Cl} \)
\( \ce{CH2=CHCH2Br} \)
4

Which halide produces a racemic mixture when reacting with \( \ce{OH^-} \) via \( \ce{S_N1} \)?

\( \ce{CH3CHClCH2CH3} \) (2-chlorobutane) forms a planar carbocation via \( \ce{S_N1} \), leading to a racemic mixture of 2-butanol.

\( \ce{CH3CH2CH2Cl} \)
\( \ce{(CH3)3CCl} \)
\( \ce{CH3CHClCH2CH3} \)
\( \ce{CH3CH2CH2CH2I} \)
3

Which halide forms \( \ce{CH3CH2CH2SCH3} \) when reacted with \( \ce{NaSCH3} \) in DMSO?

\( \ce{CH3CH2CH2Br} \) undergoes \( \ce{S_N2} \) substitution with \( \ce{NaSCH3} \) to form \( \ce{CH3CH2CH2SCH3} \) (methyl propyl sulfide).

\( \ce{CH3CH2Cl} \)
\( \ce{CH3CH2CH2Br} \)
\( \ce{CH3CHBrCH3} \)
\( \ce{CH3CH2CH2CH2I} \)
2

What is the major product when \( \ce{CH3CH=CHCH2CH2CH3} \) reacts with \( \ce{HBr} \) without peroxides?

For 2-pentene (\( \ce{CH3CH=CHCH2CH2CH3} \)), \( \ce{HBr} \) adds via Markovnikov’s rule, forming \( \ce{CH3CHBrCH2CH2CH3} \) (2-bromopentane).

\( \ce{CH3CHBrCH2CH2CH3} \)
\( \ce{CH3CH2CH2CH2CH2Br} \)
\( \ce{CH2BrCH2CH2CH2CH3} \)
\( \ce{CH3CH2CHBrCH2CH3} \)
1

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