Which of the following ion has greater coagulating power for negatively charged sol?

If enthalpy change for following reaction at $$300 \mathrm{~K}$$ is $$+7 \mathrm{~kJ} \mathrm{~mol}^{-1}$$ find the entropy change of surrounding?

$$\mathrm{H}_2 \mathrm{O}_{(\mathrm{s})} \longrightarrow \mathrm{H}_2 \mathrm{O}_{(\ell)}$$

Identify the polymer obtained from

What is IUPAC name of the following compound?