The product obtained from the following sequence of reactions is
$CH_3-C\equiv CH$ $\xrightarrow{HgSO_4, H_2SO_4} A$ $\xrightarrow{NaBH_4} B$

The reaction $2CH_3COOC_2H_5 \xrightarrow{C_2H_5ONa} CH_3COCH_2COOC_2H_5 + C_2H_5OH$ is called:

An organic compound $(A)$ with molecular formula $C_8H_8O$ forms an orange-red precipitate with $2,4-DNP$ reagent and gives a yellow precipitate on heating with iodine in the presence of sodium hydroxide. It neither reduces Tollens' or Fehlings' reagent,nor does it decolourise bromine water or Baeyer's reagent. On drastic oxidation with chromic acid,it gives a carboxylic acid $(B)$ having molecular formula $C_7H_6O_2$. Identify the compounds $(A)$ and $(B)$ and explain the reactions involved.

What is the product of the following reaction?

Which one of the following is an acetal?

The major product of the following reaction sequence is