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Unit 2.2 Acids, bases and salts

5 dot points across 5 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

What makes a solution acidic or alkaline, and how does the pH scale measure it?

Describe the properties of acids and bases, the ions they produce in solution, and use the pH scale and indicators to classify solutions.
A focused answer to WJEC GCSE Chemistry topic 2.2, covering the properties of acids and bases, the hydrogen and hydroxide ions they produce in solution, the pH scale, and using universal indicator and a pH meter to classify solutions.
8 min answer →

What does neutralisation produce, and what are the products when acids react with metals, bases and carbonates?

Describe neutralisation in terms of hydrogen and hydroxide ions and write equations for reactions of acids with metals, bases and carbonates.
A focused answer to WJEC GCSE Chemistry topic 2.2, covering neutralisation as the reaction of hydrogen ions with hydroxide ions, and the products and equations when acids react with metals, with bases, and with carbonates.
9 min answer →

How do we prepare a pure, dry sample of a soluble salt and of an insoluble salt?

Describe how to prepare a pure, dry soluble salt from an acid and an insoluble base or carbonate, and how to make an insoluble salt by precipitation.
A focused answer to WJEC GCSE Chemistry topic 2.2, covering the method for preparing a pure dry soluble salt by reacting an acid with excess insoluble base or carbonate and crystallising, and making an insoluble salt by precipitation.
9 min answer →

How do we test for halide ions, sulfate ions and carbonate ions?

Describe tests for halide ions using silver nitrate, sulfate ions using barium chloride, and carbonate ions using dilute acid.
A focused answer to WJEC GCSE Chemistry topic 2.2, covering the tests for halide ions with acidified silver nitrate, sulfate ions with acidified barium chloride, and carbonate ions with dilute acid and limewater.
8 min answer →

How do we test for common gases and identify metal ions by flame tests and with sodium hydroxide?

Describe tests for hydrogen, oxygen, carbon dioxide and chlorine, flame tests for metal ions, and tests for metal cations using sodium hydroxide solution.
A focused answer to WJEC GCSE Chemistry topic 2.2, covering the standard tests for hydrogen, oxygen, carbon dioxide and chlorine, flame tests for metal ions, and identifying metal cations by the colour of their hydroxide precipitates with sodium hydroxide.
9 min answer →