0.2 Faradays of electricity were passed through solutions of sulphuric acid. Calculate the volume of hydrogen evolved at s.t.p in sulphuric acid.
1 Faraday is = 96485.3365 coulombs
number molecules H2= 1/2 moles electrons
= 1/2 * .2* 96485/1.6E-19
make sense?
Two electrons per molecule H2 evolved.
Now number of moles= molecules/avagnumber
volume= nRT/P
To calculate the volume of hydrogen evolved at standard temperature and pressure (STP) in sulphuric acid, we'll need to apply a few steps.
Step 1: Convert Faradays to moles of electrons:
Since 1 Faraday is equivalent to the charge of 1 mole of electrons, 0.2 Faradays of electricity corresponds to 0.2 moles of electrons.
Step 2: Determine the stoichiometry of the reaction:
From the balanced chemical equation, we know that for every 1 mole of electrons passed through the cell, 1 mole of hydrogen gas (H2) is evolved.
The balanced equation for the electrolysis of water is:
2H2O(l) -> 2H2(g) + O2(g)
Step 3: Calculate the moles of hydrogen gas evolved:
Since the stoichiometry of the reaction is 1 mole of electrons to 1 mole of hydrogen gas, the moles of hydrogen gas evolved will also be 0.2 moles.
Step 4: Convert moles to volume at STP:
At STP, 1 mole of any ideal gas occupies 22.4 liters.
So, 0.2 moles of hydrogen gas would occupy:
0.2 moles x 22.4 L/mole = 4.48 L of hydrogen gas
Therefore, when 0.2 Faradays of electricity are passed through solutions of sulphuric acid, the volume of hydrogen gas evolved at STP in sulphuric acid is 4.48 liters.