The reaction shown below is known as:-
$C_6H_5COCl + H_2 \xrightarrow{Pd-BaSO_4} C_6H_5CHO + HCl$
(Benzoyl chloride $\rightarrow$ Benzaldehyde)

Consider the following statements. Which of the following reactions can be used to prepare acetophenone?
$I.$ Oxidation of $1$-phenylethanol.
$II.$ Reaction of benzaldehyde with methyl magnesium bromide.
$III.$ Friedel-Crafts acylation of benzene with acetyl chloride.
$IV.$ Distillation of calcium benzoate.
Which of these statements are correct?

Explain the method of preparation of aldehydes and ketones from acyl chloride (acid chloride) compounds with suitable examples.

Which sequence represents the best synthesis of hexanal?
$CH_3CH_2CH_2CH_2CH_2CH=O$ (Hexanal)

The major products $P$ and $Q$ in the following reactions are:
$C_6H_5-CH=NOH$ $\xrightarrow{(i) (CH_3CO)_2O} P$ $\xrightarrow{(i) CH_3MgI, (ii) H_3O^+} Q$

Etard reaction in the following is :