Identify the reagent used for the preparation of benzophenone from benzonitrile.

For the reaction sequence: $P$ $\xrightarrow[2. H_3O^+]{1. CH_3MgBr} R$ $\xrightarrow[2. \Delta]{1. \text{dil. } NaOH} \text{4-methylpent-3-en-2-one}$,identify $P$.

Which one of the combinations will give propanaldehyde on dry distillation?

Identify product $Z$ in the following reaction sequence:
$CH_2=CH-CH_2Br$ $\xrightarrow{NaCN} Y$ $\xrightarrow[1. C_6H_5MgBr, \text{diethylether}]{2. H_3O^{+}} Z$

Match List-$I$ with List-$II$:

List-$I$	List-$II$
$A$. $RCN \xrightarrow[(ii) H_3O^+]{(i) SnCl_2, HCl} RCHO$	$I$. Etard reaction
$B$. $C_6H_5COCl \xrightarrow{H_2, Pd-BaSO_4} C_6H_5CHO$	$II$. Gatterman-Koch reaction
$C$. $C_6H_5CH_3 \xrightarrow[(ii) H_3O^+]{(i) CrO_2Cl_2, CS_2} C_6H_5CHO$	$III$. Rosenmund reduction
$D$. $C_6H_6 \xrightarrow[(ii) \text{anhydrous } AlCl_3/CuCl]{(i) CO, HCl} C_6H_5CHO$	$IV$. Stephen reaction

Choose the correct answer from the options given below:

Consider the following reactions:
$C_2H_2 + H_2O \xrightarrow[333 \ K]{Hg^{2+} / H^{+}} [X] \stackrel{\text{Isomerisation}}{\rightleftharpoons} Y$
$Y$ cannot be obtained from which of the following reactions?