How much aluminum needs to be dissolved in hydrochloric acid to obtain 5.6 liters of hydrogen.

Aluminum enters into an active reaction with hydrochloric acid. In this case, an aluminum chloride salt can be obtained and hydrogen gas bubbles are released. The reaction is described by the following equation.

Al + 3HCl = AlCl3 + 3/2 H2;

Let’s determine the chemical amount of the evolved gaseous hydrogen.

For this purpose, we find the ratio of its volume to the volume of 1 mole of gas (filling a space with a volume of 22.4 liters).

N H2 = 5.6 / 22.4 = 0.25 mol;

To obtain such an amount of hydrogen, it is necessary to dissolve 0.25 x 2/3 = 0.1666 mol of aluminum.

Let’s find its mass.

M Al = 27 grams / mol;

m Al = 27 x 0.1666 = 4.5 grams;