Determine the mass of the salt obtained by the interaction of 16.8 g of potassium hydroxide with phosphoric acid.

Let’s execute the solution:

1.According to the condition of the problem, we write the data:

3KOH + H3PO4 = K3PO4 + 3H2O – the potassium phosphate salt is formed by ion exchange;

We make calculations:
M (KOH) = 56.1 g / mol;

M (K3PO4) = 212.2 g / mol.

Determine the amount of the original substance:
Y (KOH) = m / M = 16.8 / 56, 1 = 0.3 mol.

4. Proportion:

0.3 mol (KOH) – X mol (K3PO4);

-3 mol -1 mol hence, X mol (K3PO4) = 0.3 * 1/3 = 0.1 mol.

Find the mass of salt:
m (K3PO4) = Y * M = 0.1 * 212.2 = 21.22 g

Answer: the mass of potassium phosphate is 21.22 g