Answer :
Answer : The barometric pressure at the time the gas collected is, 760 mmHg
Explanation :
According to the Dalton's Law of partial pressure, the total pressure of a mixture of gases is equal to the sum of the partial pressures of the component gases.
[tex]P_T=P_{H_2}+P_{H_2O}[/tex]
where,
[tex]P_T[/tex] = total pressure
[tex]P_{H_2}[/tex] = partial pressure of hydrogen gas = 742.5 mmHg
[tex]P_{H_2O}[/tex] = partial pressure of water vapor at [tex]20.0^oC[/tex] = 17.5 mmHg (standard value)
Now put all the given values in the above expression, we get:
[tex]P_T=742.5mmHg+17.5mmHg[/tex]
[tex]P_T=760mmHg[/tex]
Therefore, the barometric pressure at the time the gas collected is, 760 mmHg