How many electrons are needed to reduce $\mathrm{N}_2$ to $\mathrm{NH}_3 ?$

The bond order of $\mathrm{HeH}^{+}$is

An egg takes 4.0 minutes to boil at sea level where the boiling point of water is $T_1 K$, where as it takes 8.0 minutes to boil on a mountain top where the boiling point of water is $\mathrm{T}_2 \mathrm{~K}$. The activation energy for the reaction that takes place during the boiling of egg is

As per the following equation, 0.217 g of HgO (molecular mass $=217 \mathrm{~g} \mathrm{~mol}^{-1}$ ) reacts with excess iodide. On titration of the resulting solution, how many mL of 0.01 M HCl is required to reach the equivalence point?

$\mathrm{HgO}+4 \mathrm{I}^{-}+\mathrm{H}_2 \mathrm{O} \longrightarrow \mathrm{HgI}_4{ }^{2-}+2 \mathrm{OH}^{-}$