Hoshi's exam strategy: cover every question type before you walk into the hall. This post has all the important questions from Acids, Bases and Salts — fill in the blanks, true/false, 1-mark, 2-mark, 3-mark, MCQs, and application questions. Work through these before your exam and you'll be ready for anything. If you haven't read the basics yet, start with our post on what acids, bases, and salts are before attempting these questions.
📌 How to use this page: Type your answer, then click "Check". Try yourself before looking at the answer. This active recall method helps you remember far better than just reading notes.
1. Substances that taste sour are called ___.
2. Substances that taste bitter and feel soapy are called ___.
3. Blue litmus turns ___ in the presence of an acid.
4. Red litmus turns ___ in the presence of a base.
5. Litmus is extracted from ___.
6. Turmeric turns ___ in the presence of a base.
7. The reaction between an acid and a base is called ___.
8. Acid + Base → ___ + Water.
9. The acid present in lemon juice is ___ acid.
1. All acids are harmful and dangerous.
2. Turmeric changes colour in acidic solutions.
3. Neutralisation produces salt and water.
4. Baking soda is an acid.
5. A neutral solution changes the colour of both blue and red litmus paper.
Q: What is an acid?
Q: What is neutralisation?
Q: Myra's mother accidentally spilled some acidic liquid on the kitchen floor. What should Myra use to clean it safely? Explain why.
Q: Hoshi noticed that the soil in his garden was too acidic and plants were not growing well. What would you advise him to do?
Your Score
Done with the questions? Go through the complete Class 7 notes on acids, bases, and salts to revise all concepts in one place. You can also brush up on how indicators work by reading our post on litmus, turmeric, and China rose indicators.
The most important topics are: (1) definitions of acids, bases, and salts, (2) properties and examples of each, (3) indicators — litmus, turmeric, China rose and their colour changes, (4) neutralisation reaction and its equation, and (5) real-life applications of neutralisation. You can read about all of these in our Class 7 notes on acids, bases, and salts.
Acid + Base → Salt + Water. This is the general neutralisation equation. Example: Hydrochloric acid + Sodium hydroxide → Sodium chloride + Water.
1. Litmus: Blue litmus → red in acid; Red litmus → blue in base. 2. Turmeric: No change in acid; turns red in base. 3. China rose: Dark pink/magenta in acid; green in base. Read our detailed post on indicators in science to learn more about each one.
Lime (calcium hydroxide) is a base. When added to acidic soil, it neutralises the excess acid through a neutralisation reaction. This makes the soil suitable for crop growth.
Baking soda is sodium bicarbonate — used in cooking and as an antacid. Washing soda is sodium carbonate — used for cleaning. Both are bases, but washing soda is more strongly basic. To understand more about how bases differ from acids, read our post on the difference between acids and bases.