When acetylene is passed through dilute sulfuric acid containing mercuric sulfate,determine the number of $\pi$-bonds in the product formed.

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:

How many carbons are in the simplest alkyne having two side chains?

$A$ compound $C_5H_8$ gives a white precipitate with ammoniacal $AgNO_3$. It yields $(CH_3)_2CHCOOH$ upon oxidation with hot alkaline $KMnO_4$. The compound is:

Which of the following contains acidic hydrogen?

Identify the major product $A$ in the following reaction sequence:
$CH_3-CH=CH-CH_3$ $\xrightarrow[CCl_4]{Br_2}$ $\xrightarrow[(ii) NaNH_2]{(i) alc. KOH} (A)$