Identify A,B and C in the following reaction sequence. A → PCl 5 B → alc . KOH C → H 2 / Ni CH 3 CH 2 CH 3

In the given reaction sequence, C is hydrogenated to form CH 3 CH 2 CH 3 . Hence C is CH 2 = CH - CH 3 . Alkyl halides undergo dehydrohalogenation reaction in presence of alcoholic KOH to form unsaturated compound. Hence, B is CH 3 CH 2 Cl . Alcohols on reaction with phosphorus halides, forms alkyl halides. Hence, A is CH 3 CH 2 OH . The reaction sequence is: CH 3 CH 2 OH → PCl 5 CH 3 CH 2 Cl → alc . KOH CH 2 = CH - CH 2 → H 2 / Ni CH 3 CH 2 CH 3

Identify A,B and C in the following reaction sequence. A → KCN B → 4 H CH 3 CH 2 CH 2 NH 2

In the given reaction sequence, B is reduced to CH 3 CH 2 CH 2 NH 2 . Alkyl cyanides of reduction gives amine. Hence, B is CH 3 CH 2 CN . Alkyl halides on reaction with potassium cyanide gives alkyl cyanides. This is a nucleophilic substitution reaction. Hence, A is an alkyl halide CH 3 CH 2 X , where X is a halogen. The reaction sequence is given by: CH 3 CH 2 X → KCN CH 3 CH 2 CN → 4 H CH 3 CH 2 CH 2 NH 2

Identify A,B and C in the following reaction sequence. A → alc . KOH B → Cl 2 C → AgOH CH 2 OH - CH 2 OH

Alkyl halides when treated with AgOH , are hydrolysed to alcohols. CH 2 X - CH 2 X + AgOH → CH 2 OH - CH 2 OH + AgX Hence, C is CH 2 Cl - CH 2 Cl as chlorine is added in the previous step. Ethene on chlorination gives 1,2-dichloroethane. Hence, B is ethene. Alkyl halides undergo dehydrohalogenation reaction in presence of alcoholic KOH to produce unsaturated compounds. Hence, A is CH 3 CH 2 X . Where, X is any halogen. Thus, the reaction sequence is: CH 3 CH 2 X → alc . KOH CH 2 = CH 2 → Cl 2 CH 2 Cl - CH 2 Cl → AgOH CH 2 OH - CH 2 OH

Identify A,B and C in the following reaction sequence. C 2 H 5 OH → ∆ conc . H 2 SO 4 A → Br 2 B → alc . KOH C

Concentrated sulphuric acid ( H 2 SO 4 ) is a dehydrating agent. Hence, alcohols on reaction with concentrated sulphuric acid gives alkenes. Thus, A is ethene. Ethene on treatment with bromine gives addition product 1,2-Dibromoethane. Hence, B is 1,2-Dibromoethane. Alkyl halides undergo dehydrohalogenation reaction in presence of alcoholic KOH to produce unsaturated product. Hence, C is ethene. The reaction sequence is: C 2 H 5 OH → ∆ conc . H 2 SO 4 CH 2 = CH 2 → Br 2 CH 2 Br - CH 2 Br → alc . KOH CH 2 = CH 2

Identify A,B and C in the following reaction sequence. C 2 H 5 I → alc . KOH A → Br 2 B → KCN C

Alkyl halides undergo dehydrohalogenation reaction in presence of alcoholic KOH to produce unsaturated product. Hence, A is ethene. Ethene on treatment with bromine gives addition product 1,2-Dibromoethane. Hence, B is 1,2-Dibromoethane. Alkyl halides on reaction with KCN gives alkyl cyanides. Hence, C is 1,2-dicyano ethane ( NC - CH 2 - CH 2 - CN ) The reaction sequence is: C 2 H 5 I → alc . KOH CH 2 = CH 2 → Br 2 BrCH 2 - CH 2 Br → KCN NCCH 2 - CH 2 CN