Reactions of acids

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Question 21
Medium

This question is about acids and bases.

a.

Give the chemical formula of the ion produced by all acids in aqueous solution that is responsible for their acidic properties.

[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 0.0850 mol/dm30.0850\text{ mol/dm}^30.0850 mol/dm3 barium hydroxide solution is completely neutralised by 21.5 cm321.5\text{ cm}^321.5 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.
[3]
c.

An aqueous solution of hydrochloric acid with pH 4.2\text{pH } 4.2pH 4.2 has a hydrogen ion concentration of 6.31×10−5 mol/dm36.31 \times 10^{-5}\text{ mol/dm}^36.31×10−5 mol/dm3.

What is the concentration of H+\text{H}^+H+. ions in a solution of hydrochloric acid with pH 1.2\text{pH } 1.2pH 1.2?

[2]

Reactions of acids Questions

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