An organic acid $P$ $(C_{11}H_{12}O_2)$ can easily be oxidized to a dibasic acid which reacts with ethylene glycol to produce a polymer,dacron. Upon ozonolysis,$P$ gives an aliphatic ketone as one of the products. $P$ undergoes the following reaction sequences to furnish $R$ via $Q$. The compound $P$ also undergoes another set of reactions to produce $S$.
$(1)$ The compound $R$ is
$(2)$ The compound $S$ is
Give the answer for questions $(1)$ and $(2)$.

The product $(P)$ of the given reaction is:

Match the reactions given in Column-$I$ with the appropriate reagents in Column-$II$.
| Column-$I$ (Reaction) | Column-$II$ (Reagent) |
| :--- | :--- |
| $(A)$ $2CH_3COOH \rightarrow (CH_3CO)_2O$ | $(i)$ $(I) NH_3, (II) \Delta, -H_2O$ |
| $(B)$ Phthalic acid $\rightarrow$ Phthalamide | $(ii)$ $(I) Br_2 / \text{red phosphorous}, (II) H_2O$ |
| $(C)$ $CH_3CH_2COOH \rightarrow CH_3CHBrCOOH$ | $(iii)$ $Br_2 / FeBr_3$ |
| $(D)$ Benzoic acid $\rightarrow$ $m$-Bromobenzoic acid | $(iv)$ $H^+, \Delta \text{ OR } P_2O_5, \Delta$ |

The major product expected when Phthalamide is treated with $NaOH$ is:

Which of the following undergoes decarboxylation most readily on being heated?

What is the product of the following reaction?