Give the product of the following reaction sequence:

$H_2 + CO +$ alkene $\xrightarrow{\text{catalyst}} 1^\circ$ alcohol. What is the stable intermediate and the nature of the reaction?

What is obtained from the Stephen reaction of alkyl cyanide?

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

Identify product $B$ in the following reaction:
Benzonitrile $\xrightarrow[\text{Dry ether}]{C_6H_5MgBr} A$ $\xrightarrow{H_3O^{+}} B$

Which of the following reactions does not produce benzaldehyde?