A technician makes solutions of three ionic compounds for electrolysis demonstrations.
| Compound | Formula |
|---|---|
| sodium chloride | NaCl |
| magnesium chloride | MgCl2\mathrm{MgCl_{2}}MgCl2 |
| aluminium sulfate | Al2(SO4)3\mathrm{Al_{2}(SO_{4})_{3}}Al2(SO4)3 |
Explain why solid magnesium chloride does not conduct electricity but a solution of magnesium chloride does.
Determine the total number of moles of ions released when 1 mol of each compound in the table dissolves in water.
The technician dissolves 9.50 g of magnesium chloride in water. Calculate the number of chloride ions in the solution. Relative atomic masses: Mg = 24, Cl = 35.5. Avogadro constant = 6.02 × 1023 per mol
The technician then makes three solutions. Each solution contains 0.1 mol of one of the compounds dissolved in water to make 1 dm3\mathrm{dm^{3}}dm3 of solution. Suggest which solution conducts electricity best. Justify your answer.
56 exam-style questions on Edexcel GCSE Chemistry 2.3 Ionic bonding, covering 2.3.1 Ions and the formation of ionic bonds, 2.3.2 Naming and deducing formulae of ionic compounds, and 2.3.3 Giant ionic lattices. Each one has a worked solution and a mark scheme showing where the marks go.