Important Questions for Class 7 Chapter 5 - Acids, Bases and Salts

Are you trying to prepare yourself well in any science topic by practicing the answers? We will make it easy for you. The solutions are provided by subject experts in a step-by-step fashion for each chapter in all the subjects. Further, these solutions are available for free. Download now!

Important questions based on NCERT syllabus for Chapter 5 - Acids, Bases and Salts:

Question-1: How do we test whether a substance is an acid or base? Give example of some substances that can be used for testing acids and bases.

Solution: For testing whether a substance is an acid or base, we use indicators. Indicators are special substances that show a change of color or smell when added to a solution containing an acidic or a basic substance. Examples of indicators are: Turmeric, litmus, China rose petals, vanillin etc.

Question-2: We brush our teeth with toothpaste that are basic in nature. Explain why?

Solution: The bacteria present in our mouth produce acid which tend to decay our tooth. The basic compounds present in our toothpaste neutralize the acids produced by the bacteria and prevents the decay of our tooth. Hence our toothpastes are basic in nature so that we can prevent tooth decay.

Question-3: What are indicators used for? Give some examples of naturally occurring indicators.

Solution: Substances that are used to differentiate between an acid and a base are called indicators. Indicators change their color when added to an acidic solution or a basic solution and this color change is different for acids and bases. Thus they help us in deciding whether a given solution is acidic or basic in nature. Some of the naturally occurring indicators are China rose petals, litmus, turmeric, etc.