What is enthalpy of formation of $$\mathrm{NH}_3$$ if bond enthalpies are as $$(\mathrm{N} \equiv \mathrm{N})=941 \mathrm{~kJ},(\mathrm{H}-\mathrm{H})=436 \mathrm{~kJ},(\mathrm{N}-\mathrm{H})=389 \mathrm{~kJ}$$ ?

Which of the following alkyl halide is treated with sodium metal to obtain $$2,2,3,3$$ - tetramethyl butane?

Electrical conductance due to all the ions in $$1 \mathrm{~cm}^3$$ of given solution is called as

For the reaction $$\mathrm{N}_{2(\mathrm{~g})}+3 \mathrm{H}_{2(\mathrm{~g})} \rightarrow 2 \mathrm{NH}_{3(\mathrm{~g})}$$, what is the relation between $$\frac{\mathrm{d}\left[\mathrm{N}_2\right]}{\mathrm{dt}}$$ and $$\frac{\mathrm{d}\left[\mathrm{H}_2\right]}{\mathrm{dt}}$$ ?