What mass of phosphoric acid will react with 240 g of sodium hydroxide?

1. Let us write down the equation of the proceeding reaction:

3NaOH + H3PO4 = Na3PO4 + 3H2O;

2.Calculate the chemical amount of sodium hydroxide:

n (NaOH) = m (NaOH): M (NaOH);

M (NaOH) = 23 + 16 + 1 = 40 g / mol;

n (NaOH) = 240: 40 = 6 mol;

3. Determine the amount of acid reacted:

n (H3PO4) = n (NaOH): 3 = 6: 3 = 2 mol;

4.Calculate the mass of phosphoric acid:

m (H3PO4) = n (H3PO4) * M (H3PO4);

M (H3PO4) = 3 + 31 + 4 * 16 = 98 g / mol;

m (H3PO4) = 2 * 98 = 196 g.

Answer: 196