How much hydrogen can be extracted from water using 0.69 g of sodium?

Let’s find the amount of sodium substance Na.

n = m: M.

M (Na) = 23 g / mol.

n = 0.69 g: 23 g / mol = 0.03 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

0.03 mol Na – x mol H2

x mol H2 = (0.03 × 1): 2 = 0.015 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 = 0.015 mol × 22.4 L / mol = 0.336 L.

Answer: 0.336 l.