Answer the following: Identify the compounds [A], [B] and [C] in the following reaction sequence…
Chemistry20275 marksIdentify
Answer the following:
(a)[1.6666666666666667]
Identify the compounds [A], [B] and [C] in the following reaction sequence:
$\text{CH}_3\text{C}\equiv\text{N} \xrightarrow{\text{SnCl}_2/\text{HCl}} [\text{A}] \xrightarrow{\text{H}_2\text{O}} [\text{B}] \xrightarrow{\text{CH}_3\text{MgBr}/\text{H}_2\text{O}} [\text{C}]$
(b)[1.6666666666666667]
Identify the compounds [A], [B] and [C] in the following reaction sequence:
$\text{H}-\text{C}\equiv\text{C}-\text{H} \xrightarrow[\text{H}_2\text{SO}_4]{\text{Hg}^{2+}} [\text{A}] \xrightarrow[\text{H}_2\text{SO}_4]{\text{K}_2\text{Cr}_2\text{O}_7} [\text{B}] \xrightarrow{\text{PCl}_5} [\text{C}]$
(c)[1.6666666666666667]
Write chemical equations to convert the following:
(1) Acetone to propene
(2) Benzaldehyde to cinnamic acid
Answer
Answer (b)
Official answer key
A - ethanal: CH3CHO
B - acetic acid: CH3COOH
C - acetyl chloride: CH3COCl
Hydration of ethyne with $\mathrm{Hg^{2+}/H_2SO_4}$ gives ethanal [A]; oxidation with acidified $\mathrm{K_2Cr_2O_7}$ gives ethanoic acid [B]; $\mathrm{PCl_5}$ converts it to ethanoyl chloride [C].
(1) Acetone to propene: reduction with $\mathrm{LiAlH_4}$ gives propan-2-ol, which on heating with conc. $\mathrm{H_2SO_4}$ at 443 K gives propene.
(2) Benzaldehyde to cinnamic acid (Perkin reaction): $\mathrm{C_6H_5CHO + (CH_3CO)_2O \xrightarrow{CH_3COONa,\ heat} C_6H_5CH=CHCOOH + CH_3COOH}$