A gardener shakes soil samples with distilled water and measures the pH of each liquid. The liquid from the vegetable patch has a pH of 6. The table shows the pH of the liquid from four flower beds.
| Flower bed | pH |
|---|---|
| W | 4 |
| X | 5 |
| Y | 7 |
| Z | 8 |
The liquid from one flower bed has a concentration of H+\mathrm{H^+}H+ ions 100 times higher than the liquid from the vegetable patch. The liquid from another flower bed has a concentration of H+\mathrm{H^+}H+ ions 10 times lower than the liquid from the vegetable patch.
Which option identifies these two flower beds?
100 times higher: X; 10 times lower: Z.
100 times higher: W; 10 times lower: X.
100 times higher: W; 10 times lower: Y.
100 times higher: Z; 10 times lower: X.
112 exam-style questions on OCR GCSE Chemistry 3.3 Types of chemical reactions, covering 3.3.1 Oxidation and reduction in terms of oxygen, 3.3.2 Acids, alkalis and neutralisation, 3.3.3 The pH scale and measuring pH, 3.3.4 Oxidation and reduction in terms of electrons, 3.3.5 Dilute and concentrated, weak and strong acids, and 3.3.6 Hydrogen ion concentration and pH. Each one has a worked solution and a mark scheme showing where the marks go.