56 g of 20% Koh solution reacts with H2So4. Find the mass of the resulting salt.

univerkov | September 12, 2021 | education

1.Let’s find the mass of KOH in the solution.

W = m (substance): m (solution) × 100%, hence

m (substance) = (m (solution) × W): 100%.

m (substance) = (56 g × 20%): 100% = 11.2 g.

1.Let’s find the amount of substance KOH.

M (KOH) = 56 g / mol.

n = 11.2 g: 56 g / mol = 0.2 mol.

Let’s find the quantitative ratios of substances.

2KOH + H2SO4 = K2SO4 + 2H2O.

For 2 mol of KOH, there is 1 mol of K2SO4.

Substances are in quantitative ratios of 2: 1.

The amount of K2SO4 is 2 times less than the amount of KOH.

n (K2SO4) = ½ n (KOH) = 0.2: 2 = 0.1 mol.

Let’s find the mass of K2SO4.

M (K2SO4) = 174 g / mol.

m = n × M.

m = 174 g / mol × 0.1 mol = 17.4 g.

Answer: 17.4 g.

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