What is reactant $A$?

When acetaldehyde is heated with Fehling's solution,it gives a red precipitate of:

Acetone on heating with $CrO_3$ mainly forms,

Phenylmagnesium bromide,upon reaction with a compound $X$ followed by treatment with acid,gives benzyl alcohol. The compound $X$ is

Which one of the following reacts with $HCN$ and Tollen's reagent,but is not oxidised by Fehling's solution?

$CH_3COOH$ $\xrightarrow{LiAlH_4} X$ $\xrightarrow{Cu, 300^{\circ}C} Y$ $\xrightarrow{\text{Dilute } NaOH} Z$. In the above reaction,$Z$ is: