Question

What is the increase in temperature necessary for a hydrogen gas, initially at 0°C, to increase its volume by 5% at constant pressure?

Answer 1

Do you assume H2 is an ideal gas? (V1/T1) = (V2/T2)
For V1 use ANY convenient number, say 100 mL. Then for V2 you use 105. T1 is 273; T2 will be in kelvin.