<u>Answer:</u> The amount of hydrogen gas collected will be 0.074 g
<u>Explanation:</u>
We are given:
Vapor pressure of water = 23.78 mmHg
Total vapor pressure = 742 mmHg
Vapor pressure of hydrogen gas = Total vapor pressure - Vapor pressure of water = (742 - 23.78) mmHg = 718.22 mmHg
To calculate the amount of hydrogen gas collected, we use the equation given by ideal gas which follows:

where,
P = pressure of the gas = 718.22 mmHg
V = Volume of the gas = 0.955 L
T = Temperature of the gas = ![25^oC=[25+273]K=298K](https://tex.z-dn.net/?f=25%5EoC%3D%5B25%2B273%5DK%3D298K)
R = Gas constant = 
n = number of moles of hydrogen gas = ?
Putting values in above equation, we get:

To calculate the mass from given number of moles, we use the equation:

Moles of hydrogen gas = 0.037 moles
Molar mass of hydrogen gas = 2 g/mol
Putting values in above equation, we get:

Hence, the amount of hydrogen gas collected will be 0.074 g