To carry out the above conversion,$(A)$ and $(B)$ respectively are:

Ethylidene dichloride can be prepared by the reaction of $HCl$ and

Heating a mixture of silver powder and $CHCl_3$ yields which compound?

Acetylene reacts with $HCN$ in the presence of $Ba(CN)_2$ to yield

Identify the structure of the final product $(D)$ in the following sequence of reactions:
$Ph-CO-CH_3$ $\xrightarrow{PCl_5, \Delta} A$ $\xrightarrow{3 \text{ eq. } NaNH_2/NH_3} B$ $\xrightarrow{\text{Acidify}} C$ $\xrightarrow{1. B_2H_6, 2. H_2O_2/OH^-} D$
Total number of $sp^2$ hybridised carbon atoms in product $D$ is:

When treated with ammoniacal cuprous chloride,which one among the following forms a copper derivative?