(I) For the Cannizzaro reaction, the compound must be non-enolizable aldehyde (without alpha-hydrogens). In this case, the compound undergoes disproportionation in the presence of a strong base, forming one alcohol and one carboxylic acid.
(II) A compound that reduces Tollens' reagent is an aldehyde. If it has a chiral carbon, it is asymmetric and can show optical activity.
(III) The positive iodoform test indicates the presence of a methyl ketone group (-COCH$_3$) or a structure that can undergo oxidation to form such a group.
(ii) Write the reaction involved in the following:
(I) Clemenssen reduction.
(II) Etard reaction.
(I) Clemenssen reduction involves the reduction of carbonyl compounds to hydrocarbons using zinc amalgam (Zn/Hg) and hydrochloric acid (HCl).
\[ \text{Aldehyde or Ketone} + \text{Zn/Hg} \longrightarrow \text{Alkane} \]
(II) Etard reaction involves the oxidation of methyl groups attached to aromatic rings to an aldehyde in the presence of chromium-based reagents.
\[ \text{Toluene} + \text{CrO}_2\text{Cl}_2 \longrightarrow \text{Benzaldehyde} \]
Give reasons for the following:
Benzoic acid does not undergo Friedel-Crafts reaction.
(b) HCHO is more reactive than $CH_3\text{CHO towards addition of HCN}$
(c) Vinyl group directly attached with carboxylic acid should decrease the acidity of corresponding carboxylic acid due to resonance, but on the contrary it increases the acidity.
In the given reaction sequence, the structure of Y would be: