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 $P$.

The reduction of benzoyl chloride with $Pd$ and $BaSO_4/CaCO_3$ produces :

Match the following:
| List-$I$ | List-$II$ |
| :--- | :--- |
| $(A)$ Acid chloride to aldehyde | $(I)$ $DIBAL-H$ |
| $(B)$ Benzene to benzaldehyde | $(II)$ $CO, HCl, \text{anhyd. } AlCl_3$ |
| $(C)$ Acetylene to aldehyde | $(III)$ $HgSO_4, H_2SO_4$ |
| $(D)$ Ester to aldehyde | $(IV)$ $H_2, Pd-BaSO_4$ |

On heating glycerol with conc. $H_2SO_4$,a compound is obtained which has a bad odour. The compound is:

In the following reaction sequence,$X$ and $Y$ are:

What sequence of steps represents the best synthesis of $4-heptanol$ $(CH_3CH_2CH_2)_2CHOH$?