Ethyl ester $\xrightarrow{CH_3MgBr \text{ (excess)}} P$. The product $P$ will be

Find out the major products $A$ and $B$ from the following reaction sequence.

Match Column-$I$ with Column-$II$ :
| Column-$I$ | Column-$II$ |
| :--- | :--- |
| $(A)$ Cyclopentanone + $2,4-$$DNP$ $\xrightarrow{\text{mild } H^+}$ Cyclopentanone$-2,4-$$DNP$ derivative | $(P)$ Electrophilic substitution |
| $(B)$ $4-$phenyl$-2-$methylbutan$-2-$ol $\xrightarrow{\text{Conc. } H_2SO_4}$ $1,1-$dimethyl$-1,2,3,4-$tetrahydronaphthalene | $(Q)$ Nucleophilic substitution |
| $(C)$ $4-$chlorocyclohexanethiol $\xrightarrow{\text{Base}}$ $7-$thiabicyclo[$2.2$.$1$]heptane | $(R)$ Nucleophilic addition |

Among formic acid,acetic acid,propanoic acid and phenol,the strongest acid in water is

What are $A, B$ and $C$ in the following reactions?
Phthalic acid $+\, NH_3 \rightarrow A \xrightarrow{\Delta} B \xrightarrow{\text{High temperature}} C$

The product $D$ of the reaction is:
$CH_3Cl$ $\xrightarrow{KCN} (A)$ $\xrightarrow{H_2O} (B)$ $\xrightarrow{NH_3} (C)$ $\xrightarrow{\Delta} (D)$