Acid-Base Reactions
Acids donate protons (H+) and bases accept them. Acid-base reactions produce salt and water. The pH scale from 0-14 measures acidity: below 7 is acidic, 7 is neutral, above 7 is basic.
What You Need to Know
Key Concept Diagram
Acid + base -> salt + water (neutralisation reaction)
pH < 7 acidic, pH = 7 neutral, pH > 7 basic/alkaline
Indicators change colour to show pH (e.g. litmus, universal indicator)
Strong acids (HCl, H2SO4) fully dissociate; weak acids (acetic acid) partially dissociate
Key Vocabulary
Acid
A substance that donates hydrogen ions (H+) in solution; pH < 7
Base
A substance that accepts hydrogen ions; a soluble base is called an alkali
Neutralisation
A reaction between an acid and a base producing salt and water
pH scale
A scale from 0-14 measuring the acidity or alkalinity of a solution
Knowledge Check
Select the correct answer for each question. Click "Check Answer" to see if you are right.
Question 1
What are the products of a neutralisation reaction between an acid and a base?
Question 2
A solution has pH 3. What does this tell you?
Question 3
Hydrochloric acid (HCl) fully separates into H+ and Cl- ions in water. This makes it a:
Key Concepts Summary
- ●Acid + base -> salt + water (neutralisation reaction)
- ●pH < 7 acidic, pH = 7 neutral, pH > 7 basic/alkaline
- ●Indicators change colour to show pH (e.g. litmus, universal indicator)
- ●Strong acids (HCl, H2SO4) fully dissociate; weak acids (acetic acid) partially dissociate