🎯 Common Question Types:
- Identify the ion responsible for acidity or alkalinity (1 mark)
- State the colour of an indicator in a given solution (1-2 marks)
- Write equations showing acids ionising in water (1-2 marks)
- Explain difference between strong/weak acids (HT, 3 marks)
- Describe how to measure pH in an experiment (2-3 marks)
📝 Key Command Words:
- Name the ion: Always answer H⁺ for acidity, OH⁻ for alkalinity
- Write an equation: Show the acid releasing H⁺ with a forward arrow (→)
- Explain: Reference the concentration of H⁺ ions and how pH is affected
- Compare: Strong/weak is about ionisation; concentrated/dilute is about amount dissolved
⚠️ Common Mistakes to Avoid:
- Confusing strong/weak with concentrated/dilute — completely different properties
- Saying "pH 7 means no ions present" — equal H⁺ and OH⁻ concentrations, not zero
- Using pH meters and universal indicator interchangeably — pH meters are more accurate
- Forgetting that all alkalis are bases, but not all bases are alkalis
- Writing H₂ instead of H⁺ as the acidic ion
This exam tips covers Exam Tips for Acids and Alkalis within Acids and Alkalis for GCSE Chemistry. Revise Acids and Alkalis in Chemical Changes for GCSE Chemistry with 25 exam-style questions and 21 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 11 of 12 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
Practice questions for Acids and Alkalis
Which ion do acids produce when dissolved in water?
Explain the difference between a strong acid and a concentrated acid.
Quick recall flashcards
Name two common alkalis
Sodium hydroxide (NaOH), Potassium hydroxide (KOH)
What is universal indicator?
An indicator that shows a range of colours across the pH scale (rainbow of colours from red to purple)