Question

How many mL of 0.75 mol/L solution of phosphoric acid will be neutralized by 25 mL of 0.5 mol/L solution of sodium hydroxide?

Answer 1

How many mL of 0.75 mol/L solution of phosphoric acid will be neutralized by 25 mL of 0.5 mol/L solution of sodium hydroxide?

$$\mathrm{H_3PO_4} + 3\mathrm{NaOH} \rightarrow \mathrm{Na_3PO_4} + 3\mathrm{H_2O}$$

v (NaOH) = V*c;

v (NaOH) = 0.025 * 0.5 = 0.0125 mol

v (H₃PO₄) = 0.0125 / 3 = 0.0042 mol

V (H₃PO₄) = v / c;

V (H₃PO₄) = 0.0042 / 0.75 = 0.0055 L

**V (H₃PO₄) = 0.0055 L**