Acids Bases and Salts — Class 7 Science NCERT Solutions (Free)

Free step-by-step NCERT solutions for Class 7 Science chapter "Acids Bases and Salts" — 8 important questions with detailed answers for CBSE board exam preparation.

TL;DR: Free step-by-step NCERT solutions for Class 7 Science chapter "Acids Bases and Salts" — 8 important questions with detailed answers for CBSE board exa…

By Syllab.in · Updated Jun 14, 2026

Key Questions Covered:

Define an acid.
Define a base.
What is the pH scale? What is the pH of a neutral solution?
What is neutralisation?
Define a salt. Give three examples.
Name two natural indicators used to test acids and bases.
+ 2 more questions in the full chapter

Solutions Summary:

Question	Status
Define an acid.	✓ Solved
Define a base.	✓ Solved
What is the pH scale? What is the pH of a neutral solution?	✓ Solved
What is neutralisation?	✓ Solved
Define a salt. Give three examples.	✓ Solved
Name two natural indicators used to test acids and bases.	✓ Solved

Showing 6 of 8 questions

Q1: Define an acid.

An acid is a substance that tastes sour and turns blue litmus paper red. Examples: Hydrochloric acid (HCl), Sulphuric acid (H₂SO₄), Acetic acid (CH₃COOH). Acids release H⁺ ions in solution.

Q2: Define a base.

A base is a substance that tastes bitter and slippery, and turns red litmus paper blue. Examples: Sodium hydroxide (NaOH), Ammonia (NH₃), Calcium hydroxide (Ca(OH)₂). Bases release OH⁻ ions in solution.

Q3: What is the pH scale? What is the pH of a neutral solution?

pH scale measures the acidity or basicity of a substance. It ranges from 0 to 14. PH < 7: Acidic; pH = 7: Neutral; pH > 7: Basic Water is neutral with pH = 7.

Q4: What is neutralisation?

Neutralisation is the reaction between an acid and a base to form salt and water. Acid + Base → Salt + Water Example: HCl + NaOH → NaCl + H₂O The pH becomes 7 (neutral) after neutralisation.

Q5: Define a salt. Give three examples.

A salt is an ionic compound formed by the reaction between an acid and a base. Examples: - Sodium chloride (NaCl) - table salt - Copper sulphate (CuSO₄) - blue in colour - Ammonium chloride (NH₄Cl)

Q6: Name two natural indicators used to test acids and bases.

Natural indicators: - Litmus: Red litmus paper turns blue in base; blue litmus turns red in acid - Turmeric: Yellow turmeric paper turns red in base - Methyl orange: Changes colour from red (acid) to yellow (base)

Showing 6 of 8 questions. Visit the full page for complete solutions.