A student investigates two solutions, C and D.
They know that:
They test 2 cm32\text{ cm}^32 cm3 of each solution for the halide ion using this method:
The teacher says that the student should have used a different acid instead of dilute hydrochloric acid.
State the name of the acid the student should have used.
Explain why using dilute hydrochloric acid would affect the results of this test.
The student repeats the test for halide ions using the correct acid and silver nitrate solution.
They also test each solution using a few drops of dilute hydrochloric acid followed by a few drops of barium chloride solution.
The table shows their results.
| Solution | Observation with silver nitrate solution | Observation with barium chloride solution |
|---|---|---|
| C | yellow precipitate | no change |
| D | no change | white precipitate |
State the name of the anion in each solution:
Solution C also contains iron(III) ions, Fe3+\text{Fe}^{3+}Fe3+.
Iron(III) ions react with hydroxide ions, OH−\text{OH}^-OH−, to make a precipitate of iron(III) hydroxide.
Write the balanced ionic equation for this reaction. Include the state symbols.
Zinc sulfate solid is harmful if swallowed.
Zinc sulfate solutions with concentrations of 25 g/dm325\text{ g/dm}^325 g/dm3 are suitable for experiments in school.
Calculate the mass of zinc sulfate that should be dissolved in 65 cm365\text{ cm}^365 cm3 of water to make a solution with a concentration of 25 g/dm325\text{ g/dm}^325 g/dm3.
Use the equation:
concentration=massvolume \text{concentration} = \frac{\text{mass}}{\text{volume}} concentration=volumemassGive your answer to 2 significant figures.
Mass of zinc sulfate = … g\dots\text{ g}… g
41 exam-style questions on OCR GCSE Chemistry Identifying the products of chemical reactions. Each one has a worked solution and a mark scheme showing where the marks go.