Identify product $A$ in the following reaction: $R-C \equiv N \xrightarrow[ii) H_{3}O^{+}]{i) DIBAl-H} A$

The compound $X$ is formed by the decarboxylation of acetoacetic acid $(CH_3COCH_2COOH)$ upon heating. $X$ can also be formed by:

Which of the following reactions does not give benzaldehyde as a product?

$CH_3-COOH \xrightarrow[\Delta]{Ca(OH)_2} (A)$
Product $(A)$ is

Explain different methods of formation of benzaldehyde by chemical reactions.

The major product of the following chemical reaction is
$CH_{3}CH_{2}CN \xrightarrow[(3) Pd/BaSO_{4}, H_{2}]{(1) H_{3}O^{+}, \Delta \quad (2) SOCl_{2}} ?$