Identify homopolymer from following.

The molar conductivity of $$0.4 \mathrm{~M} \mathrm{~KCl}$$ solution is $$2.5 \times 10^5 \Omega^{-1} \mathrm{~cm}^2 \mathrm{~mol}^{-1}$$. What is the resistivity of solution?

Sunscreen lotions contains nanoparticles of

Which from following reactions converts carbonyl group of aldehydes and ketones to methylene group on treatment with zinc amalgam and concentrated $$\mathrm{HCl}$$ ?