Class 7 Science - BIHAR
Exploring Substances: Acidic, Basic and Neutral
In the Class 7 Science chapter 'Exploring Substances: Acidic, Basic and Neutral', Bihar Board students learn about the chemical nature of various substances we use daily. The chapter covers how to identify acids and bases using natural indicators like litmus, turmeric, and china rose. It explains the process of neutralization, where an acid and a base react to form salt and water, and discusses its practical applications in everyday life, such as treating ant bites and managing soil acidity. This is a scoring chapter for board exams and forms the foundation for higher-grade chemistry.
Start Learning FreeKey Concepts
Acids
Substances that taste sour and turn blue litmus paper red. Examples include lemon juice and vinegar.
Bases
Substances that taste bitter, feel soapy to touch, and turn red litmus paper blue. Examples include baking soda and soap.
Indicators
Special substances used to test whether a substance is acidic or basic, showing different colors in acidic and basic mediums.
Neutral Substances
Substances that are neither acidic nor basic and do not change the color of red or blue litmus paper, such as pure water.
Neutralization
A reaction between an acid and a base resulting in the formation of salt, water, and heat.
Important Formulas
Board Exam Info
In the Bihar Board Class 7 Science examinations, this chapter typically carries around 5 to 8 marks. Questions generally include fill in the blanks, match the following, short answer questions on neutralization in everyday life, and differentiation between acids and bases.
Frequently Asked Questions
What is the color of turmeric indicator in a basic solution?
Turmeric indicator turns bright yellow to reddish-brown (or red) when added to a basic solution.
Why does an ant bite cause irritation?
An ant bite injects formic acid into the skin, which causes irritation and pain. It can be neutralized by rubbing moist baking soda on the affected area.
Are all acids harmful to us?
No, many acids are naturally present in the food we eat, such as citric acid in oranges and lemons, and lactic acid in curd. These are safe and beneficial.
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