Calculate the molality of the solution containing nonvolatile solute if boiling point elevation of solution is 0.39 K .

[ $\mathrm{K}_{\mathrm{b}}$ of water $=0.52 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}$ ]

Which from following polymers is used to obtain rubber belts?

Identify anionic ligand from following.

The rate constant is doubled when temperature increases from $27^{\circ} \mathrm{C}$ to $37^{\circ} \mathrm{C}$. What is activation energy in kJ ?