a. The equation for the reaction of strontium hydroxide with hydrochloric acid is shown below.

Sr(OH)₂ + 2HCl SrCl₂ + 2H₂O

25.0 cm³ of a solution of strontium hydroxide was exactly neutralised by 15.00 cm³ of 0.100 mol dm^–3 hydrochloric acid. Calculate the concentration, in mol dm^–3, of the strontium hydroxide solution.

b. 20.0 cm³ of a 0.400 mol dm^–3 solution of sodium hydroxide was exactly neutralised by 25.25 cm³ of sulfuric acid. Calculate the concentration, in mol dm^–3, of the sulfuric acid. The equation for the reaction is:

H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O