H2 is produced by the reaction of 118.5 ml of a 0.8775-m solution of h3po4 according to the following equations: 2cr +
2h3po4 ? 3h2 + 2crpo4.
(a) outline the steps neccessary to determine the number of moles and mass of h2
(b)perform the calculations outlined

Explanation:

a) First we will calculate moles of phosphoric acid present in 118.5 mL of a 0.8775 M solution.

After determining the moles of phosphoric acid, we will then calculate the number pf moles of hydrogen gas by the help unitary method.

From moles of hydrogen gas mass of the hydrogen gas can be calculated easily by the formula:

=Moles of compound × molecular mass of compound

b) Moles of phosphoric acid in  in 118.5 mL of a 0.8775 M solution be n

n = 0.10398 mol

According to reaction , 2 moles of phosphoric acid gives 3 moles of hydrogen gas:

Then 0.10398 moles of phosphoric acid will give:

of hydrogen gas

0.15597 moles of hydrogen gas are produced.

Mass 0.15597 moles of hydrogen gas:

0.15597 mol × 2 g/mol=0.31194 g

0.31194 grams of hydrogen gas are produced.