Calculate wave length for emission of a photon having wave number $11516 \mathrm{~cm}^{-1}$.

Half life of a first order reaction is 1 hour. What fraction of it will remain after 3 hour?

Identify the product of following reaction.

Calculate vapour pressure of a solution containing mixture of 2 moles of volatile liquid A and 3 moles of volatile liquid $B$ at room temperature. $\left(\mathrm{P}_{\mathrm{A}}^{\circ}=420, \mathrm{P}_{\mathrm{B}}^{\circ}=610 \mathrm{~mm} \mathrm{~Hg}\right.$)