Substitution, addition, elimination and rearrangement — NEET & JEE Questions

Question 1 · difficulty L1 · recall

A reaction in which one atom or group in an organic molecule is replaced by another is called

• A. substitution
• B. addition
• C. elimination
• D. rearrangement

Question 2 · difficulty L2 · understanding

Addition reactions are most characteristic of compounds containing

• A. multiple bonds such as C=C or C≡C
• B. only saturated C-C single bonds
• C. only ionic lattices
• D. no reactive functional groups

Question 3 · difficulty L2 · understanding

An elimination reaction typically results in

• A. formation of a multiple bond by removal of atoms or groups from adjacent atoms
• B. replacement of one group by another only
• C. addition of H2 across a double bond
• D. migration of atoms without loss of any group

Question 4 · difficulty L2 · understanding

A rearrangement reaction involves

• A. reorganisation of the carbon skeleton or substituent positions within a molecule
• B. only replacement of halogen by hydroxide
• C. only addition of hydrogen
• D. always loss of carbon dioxide

Question 5 · difficulty L3 · application

The reaction $CH_3Br+OH^-\rightarrow CH_3OH+Br^-$ is best classified as

• A. substitution
• B. addition
• C. elimination
• D. rearrangement

Question 6 · difficulty L3 · application

The reaction of ethene with $Br_2$ to form 1,2-dibromoethane is an example of

• A. addition
• B. substitution
• C. elimination
• D. rearrangement

Question 7 · difficulty L3 · application

Heating an alkyl halide with alcoholic KOH commonly gives an alkene by

• A. elimination
• B. addition
• C. substitution only
• D. rearrangement only

Question 8 · difficulty L3 · application

A carbocation changes into a more stable carbocation by a hydride shift before product formation. This step is classified as

• A. rearrangement
• B. addition
• C. elimination
• D. simple substitution

Question 9 · difficulty L4 · application

Which sequence correctly matches reaction type to transformation: alkene to dibromide; alkyl bromide to alcohol; alcohol to alkene?

• A. Addition; substitution; elimination
• B. Substitution; addition; rearrangement
• C. Elimination; substitution; addition
• D. Addition; elimination; substitution

Question 10 · difficulty L4 · application

2-Bromopropane reacts with alcoholic KOH to form propene. Which bonds are effectively removed or formed in the net transformation?

• A. A C-H and C-Br are removed while a C=C forms
• B. Only C-Br is replaced by C-OH
• C. A C=C is broken and two C-H bonds form
• D. The carbon skeleton must rearrange