The student collects the H2 (g) produced by the reaction and measures the volume

The question is incomplete, the complete question is;

The student collects the H2(g) produced by the reaction and measures its volume over water at 298 K after carefully equalizing the water levels inside and outside the gas-collection tube, as shown in the diagram below. The volume is measured to be 45.6mL . The atmospheric pressure in the lab is measured as 765 torr , and the equilibrium vapor pressure of water at 298 K is 24 torr .(i) The pressure inside the tube due to the H2(g)

741 torr

Explanation:

From the question we can see that the atmospheric pressure in the lab is 765 torr.

The vapour pressure of water = 24 torr

From Dalton's law of partial pressure, we know that;

Total pressure = Pressure of the H2 + Partial pressure of water vapour

Therefore;

Pressure of H2 = Total pressure - Partial pressure of water vapour

Pressure of H2 = 765 torr - 24 torr = 741 torr

it means there are 3 atoms of oxygen

its first and third is your answer i did the qustion the fourth isnt right