how to find the pressure exerted by the hydrogen alone?

Question

and the volume of dry hydrogen at SATP?
i have room temperature=23C
room pressure =101.62kPa
volume of h2 gas & H2O vapour
collected =43.2ml
temperature of water = 23C
length of Mg ribbon = 3.00cm

Answer 1

You can correct the wet hydrogen to dry hydrogen at SATP by using
p1v1/t1 = p2v2/t2
p1 = 101.62 kPa - vapor pressure H2O at 23 C. This gives the pressure of H2 alone. You can find the vapor pressure in tables. My table gives 21.1 mm Hg so you will need to convert that to kPa.
v1 = 43.2
t1 = 23 + 273 = ?K.
p2 & t2 are SATP conditions. Solve for v2.