$R-CN \xrightarrow[(ii) H_2O]{(i) DIBAL-H} R-Y$
Consider the above reaction and identify $Y$.

The reagents used in the Etard reaction $(I)$ and the Stephen reaction $(II)$ are:

The structure of $X$ is :

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 | $(IV)$ $H_2, Pd-BaSO_4$ |

Which of the following reagents is used in the Etard reaction?

Identify the compound $C$ in the following sequence:
$(CH_3)_2CHCH_2C \equiv N$ $\xrightarrow{HCl, H_2O} \text{compound } A$ $\xrightarrow[2. H_2O]{1. LiAlH_4} \text{compound } B$ $\xrightarrow{PCC, CH_2Cl_2} \text{compound } C$