# When hydrogen interacted with chlorine, hydrogen chloride was obtained with a mass of 73 g.

**When hydrogen interacted with chlorine, hydrogen chloride was obtained with a mass of 73 g. What mass of hydrogen was spent for this?**

1.Let’s find the amount of hydrogen chloride substance by the formula:

n = m: M, where M is molar mass.

M (HCl) = 1 + 35 = 36 g / mol.

n = 73 g: 36 g / mol = 2.03 mol.

2. Let’s compose the reaction equation.

H2 + Cl2 = 2HCl.

3. Let’s find the quantitative ratios of substances.

1 mole of hydrogen reacts with 1 mole of chlorine, 2 mole of hydrogen chloride is formed.

The substances are in quantitative ratios of 1: 2.

The amount of hydrogen substance will be 2 times less than hydrogen chloride.

n (H2) = 2.03: 2 = 1.015 mol.

Or :

1 mol (H2) – 2 mol (HCl),

2.03 mol (H2) – n mol (HCl),

n mol (HCl) = (2.03 × 2): 1 = 1.015 mol.

4. Let’s find the mass of hydrogen.

m = n M.

M (H2) = 2 g / mol.

m = 1.015 × 2 g / mol = 2.03 g.

Answer: weight = 2.03 g.