Identify the final product $A$ in the given reaction sequence.

Describe different methods for the preparation of ketones with suitable chemical reactions.

In the following sequence of reactions,what is the end product $(D)$?
$C_2H_5Br$ $\xrightarrow{KCN} A$ $\xrightarrow{H_3O^{+}} B$ $\xrightarrow{LiAlH_4} C$ $\xrightarrow[573 \ K]{Cu} D$.

$Benzaldehyde$ can be obtained from $benzal$ chloride. Write reactions for obtaining $benzal$ chloride and then $benzaldehyde$ from it.

On heating a mixture of calcium acetate and calcium formate,the product formed is:

Benzonitrile $(C_6H_5CN)$ reacts with a Grignard reagent in dry ether followed by hydrolysis to form benzophenone $(C_6H_5COC_6H_5)$ along with ammonia $(NH_3)$ and hydroxymagnesium bromide $(Mg(OH)Br)$. Identify the reagent used in the above transformation.