Consider the following reactions

$Y$ can not be obtained from which of the following reaction?

Assertion (A) : Carboxylic acids are more acidic than phenols

Reason (R) : Resonance structures of carboxylate ion are equivalent, while resonance structures of phenoxide ion are not equivalent.

In the reaction sequence $Y$ is

$$ \mathrm{CH}_3 \mathrm{CO}_2 \mathrm{H} \xrightarrow[(2) \Delta]{(1) \mathrm{NH}_3} P \xrightarrow{\mathrm{Br} / \mathrm{NaOH}} Y $$

In the equation $\left(p+\frac{a}{V^2}\right)(V-b)=R T$, where $p$ is pressure, $V$ is volume, $T$ is temperature, $R$ is universal gas constant, $a$ and $b$ are constants. The dimensions of $a$ are