Reactions of acids

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Question 13
Medium

This question is about acids and bases.

a.

Give the chemical formula of the ion that is responsible for making an aqueous solution alkaline.

[1]
b.

A student performs a titration using barium hydroxide solution and dilute hydrochloric acid.

The chemical equation for this neutralisation reaction is: Ba(OH)2(aq)+2HCl(aq)→BaCl2(aq)+2H2O(l)\text{Ba(OH)}_2(\text{aq}) + 2\text{HCl}(\text{aq}) \rightarrow \text{BaCl}_2(\text{aq}) + 2\text{H}_2\text{O}(\text{l})Ba(OH)2​(aq)+2HCl(aq)→BaCl2​(aq)+2H2​O(l)

During the titration, 25.0 cm325.0\text{ cm}^325.0 cm3 of 0.120 mol/dm30.120\text{ mol/dm}^30.120 mol/dm3 barium hydroxide solution is completely neutralised by 22.4 cm322.4\text{ cm}^322.4 cm3 of hydrochloric acid.

Calculate the concentration of the hydrochloric acid in mol/dm3\text{mol/dm}^3mol/dm3. Give your final answer to 3 significant figures.

To find this, you should calculate:

  • The number of moles of barium hydroxide in 25.0 cm325.0\text{ cm}^325.0 cm3 of the solution.
  • The number of moles of hydrochloric acid that reacted.
  • The concentration of the hydrochloric acid.
[4]
c.

Aqueous hydrochloric acid with a pH 2.5\text{pH } 2.5pH 2.5 has a hydrogen ion concentration of 3.16×10−3 mol/dm33.16 \times 10^{-3}\text{ mol/dm}^33.16×10−3 mol/dm3.

What is the concentration of H+\text{H}^+H+ ions in a solution of hydrochloric acid with pH 4.5\text{pH } 4.5pH 4.5?

[2]

Reactions of acids Questions

  1. GCSE
  2. /Chemistry
  3. /Reactions of acids