<u>Answer:</u> The total amount of leftover reactants and HCl is 12.79 grams
<u>Explanation:</u>
To calculate the number of moles, we use the equation:
.....(1)
Given mass of hydrogen gas = 0.36 g
Molar mass of hydrogen gas = 2 g/mol
Putting values in equation 1, we get:

Given mass of chlorine gas = 12.41 g
Molar mass of chlorine gas = 71 g/mol
Putting values in equation 1, we get:

The chemical equation for the reaction of hydrogen gas and chlorine gas is:

By Stoichiometry of the reaction:
1 moles of chlorine gas reacts with 1 mole of hydrogen gas
So, 0.175 moles of chlorine gas will react with =
of hydrogen gas
As, given amount of hydrogen gas is more than the required amount. So, it is considered as an excess reagent.
Thus, chlorine gas is considered as a limiting reagent because it limits the formation of product.
Moles of excess reactant left (hydrogen gas) = [0.18 - 0.175] = 0.005 moles
By Stoichiometry of the reaction
1 moles of chlorine gas produces 2 moles of HCl
So, 0.175 moles of chlorine gas will produce =
moles of HCl
Now, calculating the mass of hydrogen gas left and HCl from equation 1, we get:
Molar mass of hydrogen gas = 2 g/mol
Moles of excess hydrogen gas = 0.005 moles
Putting values in equation 1, we get:

Molar mass of HCl = 36.5 g/mol
Moles of HCl = 0.350 moles
Putting values in equation 1, we get:

Total mass of HCl and leftover reactants = [12.78 + 0.01] = 12.79 g
Hence, the total amount of leftover reactants and HCl is 12.79 grams