An unsaturated hydrocarbon (A), `C_6H_(10)`, readily gives (B) on treatment with `NaNH_2` in liquid `NH_3`. When (B) is allowed to react with 1-chloropropane, a compound (C) is obtained. On partial hydrogenation in the presence of Lindar's catalyst, (C) gives (D), `C_9H_(18)`. On ozonolysis, (D) gives 2, 2-dimethylpropanal and 1-butanal. Identify compounds A, B, C and D.

Explanation

Step 1. To determine the structure of compound (D)
Since (D) with M.F. `C_9H_18` on ozonolysis gives 2-2-dimethylpropanal and 1-butanal, therefore , (D) must be 2,2-dimethyl-3-heptene.
`underset"2,2-Dimethylpropanal"(CH_3-undersetunderset(CH_3)|oversetoverset(CH_3)|C-CH)=O+O=underset"1-Butanal"(CHCH_2CH_2CH_3)underset((ii)Zn//H_2O)overset((i)O_3)larr underset("2,2-Dimethyl-3-heptane" (D, C_9H_18)) (CH_3-undersetunderset(CH_3)|oversetoverset(CH_3)|C-CH=CHCH_2CH_2CH_3)`
Step 2. To determine the structure of the compound (C )
Since alkene(D) with `MFC_9H_18` is obtained by partial reduction of compound (C ) in presence of Lindlar catalyst, therefore, (C ) must be an alkyne , i.e., 2,2-dimethyl-3-heptyne.
`underset"2,2-Dimethyl-3-heptyne(C)"(CH_3-undersetunderset(CH_3)|oversetoverset(CH_3)|C-C-=C CH_2CH_2CH_3)underset"(Lindlar's catalyst)"overset(H_2//Pd+BaSO_4)to underset("2,2-Dimethyl-3-heptene(D)"C_9H_18)(CH_3-undersetunderset(CH_3)|oversetoverset(CH_3)|C-CH=CHCH_2CH_2CH_3)`
Step 3 To determine the structure of the compound (A) and (B) .
Since an alkyne (C ) is obtained by treatment of (B) with 1-chloropropane and (B) is obtained from (A) on treatment with sodamide in liquid `NH_3`, therefore (A) must be 3,3-dimethyl-1-butyne and (B) must be sodium salt of (A) , i.e., sodium 3,3-dimethylbutynide.
`underset((M.F.=C_6H_10))underset"3,3-Dimethyl-1-butyne(A)"(CH_3-undersetunderset(CH_3)|oversetoverset(CH_3)|C-C-=CH)underset("in lin" NH_3)overset"Na"to underset"Sod. 3,3-dimethyl-butynide (B)"(CH_3-undersetunderset(CH_3)|oversetoverset(CH_3)|C-=barCNa^(+)) underset"-NaCl"overset(ClCH_2CH_2CH_3)to underset"2,2-Dimethyl-3-heptyne (C )"(CH_3-undersetunderset(CH_3)|oversetoverset(CH_3)|C-C-=C-CH_2CH_2CH_2)`
Thus, (A)=3,3-dimethyl-1-butyne, (B)=sodium 3,3-dimethylbutynide , (C )=2,2-dimethyl-3-heptyne and (D)=2,2-dimethyl-3-heptene.