Chemical ChangesKey Facts
Key Facts: Acids, Alkalis and Indicators
Part of Acids and Alkalis — GCSE Chemistry
This key facts covers Key Facts: Acids, Alkalis and Indicators 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 7 of 12 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 7 of 12
Practice
20 questions
Recall
20 flashcards
📌 Key Facts: Acids, Alkalis and Indicators
- Acids have pH less than 7 and produce H⁺ ions in solution
- Alkalis have pH greater than 7 and produce OH⁻ ions in solution
- Neutral substances have pH exactly 7 (equal H⁺ and OH⁻)
- Universal indicator shows a range of colours across the pH scale
- Litmus is red in acid, blue in alkali
- Phenolphthalein is colourless in acid, pink in alkali
- Methyl orange is red in acid, yellow in alkali
- The three common lab acids are: HCl, H₂SO₄, HNO₃
- The two common lab alkalis are: NaOH, KOH
- Concentrated = lots of acid/alkali particles per volume
- Dilute = few acid/alkali particles per volume