Acetic acid exists as a dimer in benzene solution. This is due to

$\begin{array}{*{20}{c}}
{C{H_2} - COOH} \\
{|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,} \\
{C{H_2} - COOH}
\end{array}\xrightarrow{\Delta }(A)\xrightarrow{{C{H_3} - C{H_2}N{H_2}/\Delta }}(B)$

$(B)$ will be :

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On dissolving $0.5 g$ of a non-volatile non-ionic solute to $39 g$ of benzene, its vapor pressure decreases from $650 mm Hg$ to $640 mm Hg$. The depression of freezing point of benzene (in $K$ ) upon addition of the solute is. . . . .

(Given data : Molar mass and the molal freezing point depression constant of benzene are $78 g mol ^{-1}$ and $5.12 K kg mol ^{-1}$, respectively)

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For the following electrochemical cell at $298 \mathrm{~K}$,

$\mathrm{Pt}(s) \mid \mathrm{H}_2(g, 1 \text { bar })\left|\mathrm{H}^{+}(a q, 1 \mathrm{M}) \| \mathrm{M}^{4+}(a q), \mathrm{M}^{2+}(a q)\right| \mathrm{Pt}(s)$

$E_{\text {cell }}=0.092 \mathrm{~V} \text { when } \frac{\left[\mathrm{M}^{2+}(a q)\right]}{\left[\mathrm{M}^{4+}(a q)\right]}=10^x$

Given : $ E_{\mathrm{M}^4 / \mathrm{M}^{2+}}^0=0.151 \mathrm{~V} ; 2.303 \frac{R T}{F}=0.059 \mathrm{~V}$

The value of $x$ is

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Isobutyraldehyde on reaction with formaldehyde and $K _{2} CO _{3}$ gives compound $'A'.$ Compound $'A'$ reacts with $KCN$ and yields compound $'B',$ which on hydrolysis gives a stable compound $'C'.$ The compound $'C'$ is .... .

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The reaction of acetamide with water is an example of

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In the following reactions, $P, Q, R$, and $S$ are the major products.

The correct statement ($s$) about $P, Q, R$, and $S$ is (are)

($A$) $P$ and $Q$ are monomers of polymers dacron and glyptal, respectively.

($B$) $P, Q$, and $R$ are dicarboxylic acids.