Which of the following oxides will produce hydrogen peroxide upon reaction with dilute acid?

Consider the following reaction,
$C_2H_5Cl + AgCN \xrightarrow{EtOH / H_2O} \underline{X} \text{ (major)}$
Which one of the following statements is true for $\underline{X}$?
$(I)$ It gives propionic acid on hydrolysis
$(II)$ It has an ester functional group
$(III)$ It has a nitrogen linked to ethyl carbon
$(IV)$ It has a cyanide group

The period of $f(x)=\cos \left(\frac{x}{3}\right)+\sin \left(\frac{x}{2}\right)$ is (in $pi$)

At $298 \ K$,the $emf$ of the cell is .......... $V$.
$Pt | H_{2(2 \ atm)} | H^{+}_{(0.002 \ M)} || H^{+}_{(0.1 \ M)} | H_{2(1 \ atm)} | Pt$

$H^+$,$He^+$ and $O^{++}$ are projected in a uniform transverse magnetic field with equal accelerating potential. If their masses are $1 \, a.m.u.$,$4 \, a.m.u.$ and $16 \, a.m.u.$ respectively,find the ratio of their radii.

$A$ capacitor of capacity $4 \mu F$ is charged to $80 \ V$ and another capacitor of capacity $6 \mu F$ is charged to $30 \ V$. When they are connected,the energy lost by the $4 \mu F$ capacitor is: (in $mJ$)