Science · Class 10
Acids, Bases and Salts
pH scale, indicators, salts, and their uses in daily life.
4 sections15–25 min read6 MCQs · 2 examples
Chapter Overview
Acids release H⁺ in water; bases release OH⁻. pH scale measures acidity. This chapter covers indicators, neutralisation, salts, family of salts, and important compounds like baking soda and washing soda.
Acids & Bases
Neutralisation
Acid + Base → Salt + Water
pH
pH = −log[H⁺] ; pH 7 neutral, <7 acidic, >7 basic
Strong acid
HCl, H₂SO₄, HNO₃ — ionise completely
Salts & pH
- Sodium chloride (NaCl): from HCl + NaOH
- Baking soda: NaHCO₃ — antacid, baking
- Washing soda: Na₂CO₃·10H₂O
- Bleaching powder: Ca(OCl)₂
- Plaster of Paris: CaSO₄·½H₂O
Indicators
- Litmus: red in acid, blue in base
- Phenolphthalein: colourless in acid, pink in base
- Methyl orange: red in acid, yellow in base
Solved Examples
Step-by-step solutions — read each step before checking the final answer.
Neutralisation
Write reaction of HCl and NaOH.
- 1HCl + NaOH → NaCl + H₂O
- 2H⁺ + OH⁻ → H₂O
Answer
NaCl and water formed
pH interpretation
Solution pH = 3. Acidic or basic?
- 1pH < 7 → acidic
- 2Higher [H⁺] than pure water
Answer
Acidic
Key Points to Remember
- ✓ Acids conduct electricity in aqueous solution
- ✓ Bases feel soapy; acids taste sour (don't taste in lab!)
- ✓ Tooth decay below pH 5.5
Exam Tips
- • Know preparation and uses of important salts
- • Universal indicator gives approximate pH
- • Distinguish strong vs weak acids
Practice MCQs — Acids, Bases and Salts
Test your understanding with topic-wise multiple choice questions. Explanations appear after each answer.
Question 1 of 6Score: 0/0
pH of pure water is: