Assign $A, B, C, D$ from the given type of reaction.
$PbO_2 + 4HCl \xrightarrow{\text{Warm}} PbCl_2 + Cl_2 + 2H_2O$

One mole of alkene $\underline{X}$ on ozonolysis gave one mole of acetaldehyde and one mole of acetone. The $IUPAC$ name of $\underline{X}$ is

$A$ body is executing simple harmonic motion. At a displacement $x$ its potential energy is $E_1$ and at a displacement $y$ its potential energy is $E_2$. The potential energy $(E)$ at displacement $(x+y)$ is

The ratio of rates of diffusion of gases $X$ and $Y$ is $1:5$ and that of $Y$ and $Z$ is $1:6$. The ratio of rates of diffusion of $Z$ and $X$ is

The correct order of acidic strength of the major products formed in the given reactions is:
$A.$ $PhNH_2$ $\xrightarrow[\substack{\text{(2) } CuCN \\ \text{(3) } H_3O^{+} / \Delta}]{\text{(1) } NaNO_2 + HCl \left( < 5^{\circ} C \right)} [A]$
$B.$ $CH_3CH_2CHO \xrightarrow[\Delta]{\left[ Ag \left( NH_3\right)_2\right]^{+}, OH^{-}} [B]$
$C.$ $CH_4 + O_2 \xrightarrow[\text{(ii) } Na_2Cr_2O_7 / H^{+}]{\text{(i) } Mo_2O_3} [C]$
$D.$ $PhCH_2MgBr + CO_2 \xrightarrow[H_3O^{+}]{\text{Dry ether}} [D]$
Choose the correct answer from the options given below:

If $x y \neq 0, x+y \neq 0$ and $x^m y^n=(x+y)^{m+n}$, where $m, n \notin N$, then $\frac{d y}{d x}$ is equal to