Which of the following is a mixed ketone?

The formation of cyanohydrin from ketones is an example of which type of reaction?

An optically active alkyl halide $C_4H_9Br$ $[A]$ reacts with hot $KOH$ dissolved in ethanol and forms alkene $[B]$ as the major product,which reacts with bromine to give dibromide $[C].$ The compound $[C]$ is converted into a gas $[D]$ upon reacting with alcoholic $NaNH_2.$ During hydration,$18 \ g$ of water is added to $1 \ mole$ of gas $[D]$ on warming with mercuric sulphate and dilute acid at $333 \ K$ to form compound $[E].$ The $IUPAC$ name of compound $[E]$ is $:$

Identify the compound $A$ in the following reaction: $A + CH_3MgBr$ $\xrightarrow{\text{dry ether}} \text{intermediate}$ $\xrightarrow{H_3O^+} CH_3CH_2OH + Mg(Br)(OH)$

In the reaction $CH_3CHO + HCN \to CH_3CH(OH)CN$,a chiral centre is produced. This product would be

The $K_{eq.}$ values in $HCN$ addition to the following aldehydes are in the order: