Which of the following oxides is paramagnetic?

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