Complete the equation: CH 3 - CHBr - CH 2 Br → Alc . KOH

When vicinal or 1 , 2 - dihalo compounds are treated with alcoholic potassium hydroxide, two molecules of hydrogen halides are eliminated from adjacent carbon atoms to give alkynes. CH 3 - CHBr - CH 2 Br → - HBr alc . KOH CH 3 - C Br = CH 2 → - HBr alc . KOH CH 3 - C ≡ CH

Complete the equation: HC ≡ CH + 2 Na → liq . NH 3

Acetylene and terminal alkynes react with sodamide i.e sodium in liquid ammonia, at 475 K to form disodium acetylide. This is an example of substitution reaction. HC ≡ CH + 2 Na → liq . NH 3 NaC ≡ CNa + NH 3

Complete the equation: CH 3 - C ≡ CH → HgSO 4 42 % H 2 SO 4

When propyne is passed over 42 % H 2 SO 4 at 60 ° C in the presence of HgSO 4 , an unstable compound vinyl alcohol is formed which further rearranges to form propanone. The addition takes place according to Markownikoff's rule. CH 3 - C ≡ CH → HgSO 4 42 % H 2 SO 4 [ CH 3 - C OH = CH 2 ] ⇌ CH 3 - C O - CH 3

Identify the compound A , B and C . A + H 2 O → B → ammoniacal CuCl C → dil HCl HC ≡ CH

Acetylene reacts with ammoniacal solution of copper chloride to form corresponding copper acetylide, a red precipitate. These alkynides are unstable and explode in dry state. Hence, these should be decomposed immediately with dilute mineral acid which liberates back alkynes. CaC 2 + 2 H 2 O → HC ≡ CH → ammoniacal CuCl CuC ≡ CCu → dil HCl HC ≡ CH

Identify the compound A , B and C . HC ≡ CH → Na A → CH 3 I B → Hg 2 + H + , H 2 O C

Ethyne (acetylene) reacts with sodium metal at 475 K to form monosodium acetylide A . When it reacts with methyl iodide, methyl group replaces sodium atom to form propyne B . When propyne is passed over 42 % H 2 SO 4 at 60 ° C in the presence of HgSO 4 , an unstable compound vinyl alcohol is formed which further rearranges to form propanone C . The addition takes place according to Markownikoff's rule. HC ≡ CH → Na HC ≡ CNa A → CH 3 I HC ≡ C - CH 3 B → Hg 2 + H + , H 2 O [ CH 3 - C OH = CH 2 ] ⇌ CH 3 - C O - CH 3 C

Identify the compound A , B and C . H 2 C = CH 2 + Br 2 → A → alc KOH B → 1 % HgSO 4 / 60 ° C 42 % H 2 SO 4 C

When bromine is added to ethene, addition reaction takes place. The bromine adds across the double bond to the carbon, and 1 , 2 - dibromoethane A is obtained. On treating 1 , 2 - dibromoethane with alcoholic potassium hydroxide, two molecules of potassium bromide and water is removed to form ethyne B . When ethyne is passed over 42 % H 2 SO 4 at 60 ° C in the presence of HgSO 4 , an unstable compound vinyl alcohol is formed which further rearranges to form ethanal C . H 2 C = CH 2 → Br 2 BrCH - CHBr A → - 2 KBr , - 2 H 2 O alc KOH HC ≡ CH B → 1 % HgSO 4 / 60 ° C 42 % H 2 SO 4 CH 3 - CHO C