Milk can be preserved by adding a few drops of

When ethanal reacts with $CH_3MgBr$ and $C_2H_5OH$/dry $HCl$,the products formed are

Give the best conditions for this transformation:

Compound $Figure$ $1$ formed by the reaction of furfural ($Figure$ $2$) with ethanol is:

Compound $(A)$ with molecular formula $C_6H_{12}O$ is optically active. Compound $(A)$ gives a negative Tollens test and a positive test with $2,4$-dinitrophenylhydrazine. Identify $(A)$.

The most reactive compound towards the formation of cyanohydrin on treatment with $KCN$ followed by acidification is: