This exam focus covers Exam Focus within Acids and Alkalis for GCSE Chemistry. Revise Acids and Alkalis in Chemical Changes for GCSE Chemistry with 20 exam-style questions and 20 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 10 of 12 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
Topic position
Section 10 of 12
Practice
20 questions
Recall
20 flashcards
🎯 Exam Focus
Frequently Examined
Acids and alkalis underpin much of Unit 4. Common question types include:
- Identify the ion: "Name the ion responsible for the acidity of hydrochloric acid" — always H⁺ (1 mark)
- Indicator colours: "What colour would universal indicator turn in sodium hydroxide solution?" (1-2 marks)
- Equations: Write the equation for an acid releasing H⁺ ions in water (1-2 marks)
- Higher Tier: Explain the difference between a strong and weak acid, or between concentrated and dilute (3 marks)
- Practical questions: How to measure the pH of a solution and what the reading tells you (2-3 marks)
Key phrase examiners love: "The ion responsible for acidity is H⁺ (hydrogen ions)." Learn this as a one-line answer.
Quick Check: Name the ion responsible for making a solution acidic, and the ion responsible for making it alkaline.
Acidic: H⁺ (hydrogen ions). Alkaline: OH⁻ (hydroxide ions). These are the defining ions for acidity and alkalinity respectively.
Quick Check: What colour does litmus paper turn in a solution of hydrochloric acid, and what does this indicate about its pH?
Litmus paper turns red in hydrochloric acid. This indicates the solution is acidic — pH below 7. HCl releases H⁺ ions in water.