What is standard $N \equiv N$ bond enthalpy from following reaction,

$$\begin{aligned} & \mathrm{N}_2(g)+3 \mathrm{H}_2(g) \longrightarrow 2 \mathrm{NH}_3(g) ; \Delta H^{\circ}=-83 \mathrm{~kJ} \\ & \left(\Delta H^{\circ}(\mathrm{H}-\mathrm{H})=435 \mathrm{~kJ} ; \Delta H^{\circ}(\mathrm{N}-\mathrm{H})=389 \mathrm{~kJ}\right) \\ \end{aligned}$$

Which of the following is correct decreasing order of the repulsive interaction of electron pairs in a molecule?

For first order reaction the concentration of reactant decreases from 0.2 to 0.1 M in 100 minutes. What is the rate constant of the reaction?

The end product $C$ of the following reaction is

$$\mathrm{C}_2 \mathrm{H}_5 \mathrm{NH}_2 \xrightarrow{\mathrm{HNO}_2} A \xrightarrow{\mathrm{PCl}_5} B \xrightarrow[\text { Alcohol }]{\mathrm{NH}_3} C$$