Which of the following is a Lewis base?

$A$ gas is filled in a cylinder. Its temperature is increased by $20\%$ on the Kelvin scale and its volume is reduced by $10\%$. How much percentage of the gas will leak out at constant pressure?

Given that $\Delta H_f(H) = 218 \ kJ/mol$,express the $H-H$ bond energy in $kcal/mol$.

Which of the following is $NOT$ a mode of nutrition?

The acute angle between the line $\vec{r}=(\hat{i}+2\hat{j}+\hat{k})+\lambda(\hat{i}+\hat{j}+\hat{k})$ and the plane $\vec{r} \cdot(2\hat{i}+\hat{j}+\hat{k})=5$ is

During the change of $O_2$ to $O_2^-$ ion,the electron adds to which one of the following orbitals?