Which compound on oxidation with acidic $KMnO_4$ gives Benzoic acid?

Assertion : $RCOCl$,$(RCO)_2O$ and $RCOOR'$ all react with Grignard reagents to form $3^o$ alcohols.
Reason : $RCOCl$ reacts with $R_2Cd$ to form ketones but $(RCO)_2O$ and $RCOOR'$ do not react at all.

Hydrolysis of an ester gives a carboxylic acid which on Kolbe's electrolysis yields ethane. The ester is

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 |

Number of equivalents of Grignard reagent $(x)$ used in the reaction is

Give simple chemical tests to distinguish between the following pairs of compounds.
$(i)$ Propanal and Propanone
$(ii)$ Acetophenone and Benzophenone
$(iii)$ Phenol and Benzoic acid
$(iv)$ Benzoic acid and Ethyl benzoate
$(v)$ Pentan$-2-$one and Pentan$-3-$one
$(vi)$ Benzaldehyde and Acetophenone
$(vii)$ Ethanal and Propanal