The product $(P)$ formed in the following reaction is $:$

Nucleophilic addition reaction will be most favoured in

Arrange these compounds in decreasing order of reactivity for the nucleophilic addition reaction :
$I.$ Acid chloride $II.$ Aldehyde
$III.$ Ketone $IV.$ Ester
Select the correct answer from the codes given below :

Identify the main product of the following reaction: $R - CO - O - R' \xrightarrow[H_3O^+]{DIBAL-H} \text{Product}$

Identify the product formed in the following reaction: $CH_3-CH=CH-CH_2-CHO \xrightarrow[(ii) \ H_3O^{+}]{(i) \ LiAlH_4} \text{Product}$

An aromatic compound $A$ (Molecular formula $C_{8}H_{8}O$) gives a positive $2,4-DNP$ test. It gives a yellow precipitate of compound $B$ on treatment with iodine and sodium hydroxide solution. Compound $A$ does not give Tollen's or Fehling's test. On drastic oxidation with potassium permanganate,it forms a carboxylic acid $C$ (Molecular formula $C_{7}H_{6}O_{2}$),which is also formed along with the yellow compound in the above reaction. Identify $A, B$ and $C$ and write all the reactions involved.