Calculate the cryoscopic constant of a solvent if depression in freezing point of $0 \cdot 3$ m solution of nonelectrolyte is $0 \cdot 48$ K

Identify the correct statement from following.

What is the change in oxidation number of Pb at positive electrode of lead accumulator acting as galvanic cell ?

The graphical variation of molar conductivity $(\Lambda)$ against square root of molar concentration $(\sqrt{c})$ of certain electrolyte 'X' is linear with intercept on y axis. Identify X from following.