Use the Clausius Clapeyron equation, which is derived from the Clapeyron equation for equilibria between phases.
ln(p2/p1)= (deltaH/RT1)- (deltaH/RT2)
In your problem,
Calculate for T1.
The second problem can be solved similarly.I hope i calculated correctly, the principle is right.
The Clapeyron eqn is:
for condensed phase-vapour equilibria, deltaV = molar volume of gas since, volume of gas>> volume of solid or liquid.
also, deltaS=deltaH(vap)/T, at boiling point
then use the ideal gas eqn for 1 mole, you get the Clausius-Clapeyron eqn.