Ethyl bromide is converted to succinic acid by using the following reagents in steps:-

A. KCN
B. Br₂
C. KOH(alc.)
D. H₂O/H

Choose the correct sequence of conversion-

C, B, A and D

The correct answer is Option (1) → C, B, A and D.

Ethyl bromide  to succinic acid

Step 1: Treatment with KOH (alc.) (C) 

Ethyl bromide \((C_2H_5Br)\) reacts with alcoholic potassium hydroxide \((KOH(alc.))\) via elimination reaction (\(E_2\) mechanism) to form ethene \((C_2H_4)\).

Step 2: Bromination with \(Br_2\) (B) 

Ethene undergoes bromination with bromine \((Br_2)\) to form 1,2-dibromoethane.

Step 3: Treatment with KCN (A)

1,2-Dibromoethane reacts with potassium cyanide \((KCN)\) in a nucleophilic substitution reaction, replacing both bromine atoms with cyanide groups, forming 1,2-dicyanoethane.

Step 4: Hydrolysis with \(H_2O/H^+\) (D)

1,2-Dicyanoethane undergoes acidic hydrolysis in the presence of water and acid \((H_2O/H^+)\) to form succinic acid.

Conclusion:

The correct sequence is C  → B  → A  → D.

Hence, the correct answer is:
**Option 1: C, B, A, and D.**