CUET(UG) Practice Quiz

Question 1

Which statement best explains why tertiary alkyl halides usually undergo SN1 reactions more readily than primary alkyl halides in polar protic solvents?

Accepted Answer

Tertiary carbocations are more stable due to inductive effect and hyperconjugation, so ionization is easier.

Question 2

In an SN2 reaction, the nucleophile attacks the substrate from the side opposite to the leaving group mainly because

Accepted Answer

the nucleophile must overlap with the antibonding orbital of the C–X bond from the opposite side.

Question 3

Why is vinyl chloride (CH2=CHCl) much less reactive toward nucleophilic substitution than ethyl chloride?

Accepted Answer

The C–Cl bond has partial double-bond character and the carbon is sp2 hybridized, making substitution difficult.

Question 4

During bromination of an alkene in CCl4, the anti addition of bromine is best explained by formation of

Accepted Answer

a cyclic bromonium ion that is opened by backside attack of Br-.

Question 5

The rate law for hydrolysis of tert-butyl bromide in water is rate = k[(CH3)3CBr]. This observation indicates that the reaction most likely follows

Accepted Answer

SN1 mechanism because the rate depends only on substrate concentration.

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