How much hydrogen can be obtained by dissolving 4.6 sodium in water?

Find the amount of Na by the formula:

n = m: M.

M (Na) = 23 g / mol.

n = 4.6 g: 23 g / mol = 0.2 mol.

Let’s compose the reaction equation, find the quantitative ratios of substances.

2Na + 2H2O = 2NaOH + H2.

According to the reaction equation, there is 1 mole of hydrogen per 2 mol of sodium. Substances are in quantitative ratios of 2: 1.

The amount of hydrogen will be 2 times less than sodium.

2 mol Na – 1 mol H2

0.2 mol Na – х mol H2

x mol H2 = (0.2 × 1): 2 = 0.1 mol.

Let’s find the volume of hydrogen.

V = Vn n, where Vn is the molar volume of gas, equal to 22.4 l / mol, and n is the amount of substance.

V = 0.1 mol × 22.4 L / mol = 2.24 L.

Answer: 2.24 l.