Which among the following compounds is used as selective weed killer?

Calculate the difference between heat of combustion of carbon monoxide gas at constant pressure and at constant volume at $27^{\circ} \mathrm{C} ?\left(R=2 \mathrm{cal} \mathrm{K}^{-1} \mathrm{~mol}^{-1}\right)$

The conductivity of an electrolytic solution decreases on dilution due to

Identify $B$ in the following reaction,

$$\text { Acetaldoxime } \xrightarrow[\text { alcohol }]{\mathrm{Na}} A \xrightarrow[\text { HCl }]{\mathrm{NaNO}_2} B+\mathrm{H}_2 \mathrm{O}+\mathrm{N}_2 \uparrow$$