Question

How do you calculate the partial pressure of hydrogen gas?

Answer 1

We need to know that ideal gas states that pressure and volume is directly proportional to temperature and number of moles. Dalton’s law states that: Dalton's law of partial pressures states that the total pressure of a mixture of gases is the sum of the partial pressures of its components:
${P_{total}} = {P_{gas1}} + {P_{gas2}} + {P_{gas3}} \ldots \ldots$

Complete answer:
The partial pressure law was given by Dalton’s law:
The pressure exerted by an individual gas in a mixture is known as its partial pressure. Assuming we have a mixture of ideal gases, we can use the ideal gas law to solve problems involving gases in a mixture. Dalton's law of partial pressures states that the total pressure of a mixture of gases is equal to the sum of the partial pressures of the component gases:
${P_{total}} = {P_{gas1}} + {P_{gas2}} + {P_{gas3}} \ldots \ldots$
Dalton’s law can be expressed using the mole fraction of a gas, x
${P_{gas1}} = {x_1}{P_{total}}$
Dalton’s law states that: Dalton's law of partial pressures states that the total pressure of a mixture of gases is the sum of the partial pressures of its components:
${P_{total}} = {P_{gas1}} + {P_{gas2}} + {P_{gas3}} \ldots \ldots$
Where the partial pressure of each gas is the pressure that the gas would exert if it was the only gas in the container. That is because we assume there are no attractive forces between the gases.
In a gaseous mixture, the partial pressure exerted by a component gas is the same as the pressure it would exert if it ALONE occupied the container. The total pressure is the sum of the individual partial pressures.
I have just restated Dalton's Law of Partial Pressures, and using the Ideal Gas Equation, we say that ${P_1} = {n_1}RTV,{P_2} = {n_2}RTV,..........\;{P_n} = {n_n}RTV,$etc.
And thus
${P_{Total}}\; = {P_1} + {P_2} + ..........{P_n}$
$= \;(n1 + n2 + n3.........) \times R\dfrac{T}{V}$
The partial pressure exerted by an individual component is thus proportional to ${P_{Total}}$, with the constant of proportionality being $n1 + n2 + n3 + ....$, the mole fraction.

Note:
We need to know that in a gaseous mixture, the partial pressure exerted by a component gas is the same as the pressure it would exert if it ALONE occupied the container. The partial pressure exerted by an individual component is thus proportional to ${P_{Total}}$, with the constant of proportionality being $n1 + n2 + n3 + ....$, the mole fraction.