(i) An organic compound (A) is identified as C₆H₅CHO benzaldehyde. Benzaldehyde reduces Tollen'sreagent and also undergoes. Cannizaro reaction.
\(\underset { (A) }{ C_{ 6 }{ H }_{ 5 }CHO } +{ Ag }_{ 2 }O\longrightarrow 2Ag+\underset { (B) }{ { C }_{ 6 }{ H }_{ 5 }COOH } \) 
(ii) Benzaldehyde reacts with acetic anhydride in the presence of sodium acetate gives cinnamic acid and it is (B) an unsaturated acid
\(\underset { (A) }{ { C }_{ 6 }{ H }_{ 5 }CHO } +\left( { CH }_{ 3 }CO \right) _{ 2 }O\overset { { CH }_{ 3 }COONa }{ \longrightarrow } \underset { (B) }{ { C }_{ 6 }{ H }_{ 5 }CH } { =CHCOOH }+{ CH }_{ 3 }COOH\) 
(iii) Compound A reacts with acetone to form compound (C) benzal acetone.
\(\underset {(A)}{{ C }_{ 6 }{ H }_{ 5 }CHO}+{ CH }_{ 3 }COC{ H }_{ 3 }\overset { NaOH }{ \longrightarrow } { C }_{ 6 }{ H }_{ 5 }CH=\underset { (C) }{ CH } -CO{ CH }_{ 3 }\) 

(i) From the molecular formula, (A) is identified as benzaldehyde and it is called as oil of bitter almonds.
(ii) Benzaldehyde is oxidised to benzoic acid by alkaline permanganate which gives brisk effervescence with NaHCO₃.
 \(\underset { (A) }{ { C }_{ 6 }{ H }_{ 5 }CHO } \overset { (O) }{ \longrightarrow } \underset { (B) }{ { C }_{ 6 }{ H }_{ 5 } } -COOH\)
(iii) When benzaldehyde is refluxed with aqueous alcoholic KCN, benzoin (C) is formed.
\({ C }_{ 6 }{ H }_{ 5 }CH=O+H-\overset { \underset { || }{ O } }{ C } -{ C }_{ 6 }{ H }_{ 5 }\overset { alc }{\underset{KCN} \longrightarrow } { C }_{ 6 }{ H }_{ 5 }-\underset { \overset { | }{ OH\\ (C) } }{ CH } -\overset { \underset { || }{ O } }{ C } -{ C }_{ 6 }{ H }_{ 5 }\)

(i) An organic compound A (C₂H₃N) on reduction with SnCl₂/HCI gives B (C₂H₄O) which reduces Tollens reagent.
\({ CH }_{ 3 }-C\overset { | }{ \underset { \underset { H-H\\ \quad (A) }{ | } }{ = } } N\overset { sn{ Cl }_{ 2 } }{ \underset { HCl }{ \longrightarrow } } { CH }_{ 3 }CH=NH-HCl\overset { Hydrolysis }{ \longrightarrow }\underset{(B)} {{ CH }_{ 3 }CHO}+{ NH }_{ 4 }Cl\) 
(ii) Compound B on reduction with N₂H₄/C₂H₅ONa gives C (C₂H₆).

(i) Compound (A) with molecular formula C₃H₆O that undergoes iodoform reaction is CH₃COCH₃ (A) (acetone).
(ii) Two molecules of (A) react with dry HCl to give compound (B).

(iii) Compound (B) reacts with (A) to give compound (C).

Compound	Compound Name	Formula
A	Acetone
B	Mesityl oxide
C	Phorone

(i) Compound (A) must be acetyl chloride which undergoes Rosenmund's reduction giving acetaldehyde.
\(\underset { (A) }{ { CH }_{ 3 }COCl } \overset { Pd/BaS{ O }_{ 4 } }{ \longrightarrow } \underset { (B) }{ { CH }_{ 3 }CHO } \) 
(B) undergoes iodoform reaction
\(\underset { (B) }{ { CH }_{ 3 }COH } \overset { { I }_{ 2 }/NaOH }{ \longrightarrow } \underset { Iodoform }{ { CHI }_{ 3 } } +HCOONa\) 
(ii) Acetaldehyde (B) undergoes polymerisation giving a cyclic compound.

Compound	Compound name	Formula
A	Acetyl chloride	CH3COCI
B	Acetaldehyde	CH3CHO
C	Paraldehyde