PSEB 7th Class Science Notes Chapter 5 Acids, Bases and Salts

This PSEB 7th Class Science Notes Chapter 5 Acids, Bases and Salts will help you in revision during exams.

PSEB 7th Class Science Notes Chapter 5 Acids, Bases and Salts

→ We eat many foods with different tastes in our daily life.

→ Some foods taste bitter, sour, sweet, and salty.

→ The sour taste of the substance is due to the acid present in them.

→ The word acid is derived from the Latin word ‘acere’, which means sour.

PSEB 7th Class Science Notes Chapter 5 Acids, Bases and Salts

→ Substances that have a bitter taste and are soapy to touch, are called the base.

→ Indicators are substances that give different colours to substances or solutions of acidic and basic nature.

→ They are used to test the acidic or alkaline nature of substances.

→ Turmeric, litmus, and China rose petals (Gudhal) are natural indicators.

→ Neutral solutions do not change the color of litmus red or blue because they are neither acidic nor basic.

→ Phenolphthalein is a synthetic indicator that is prepared in the laboratory.

→ Some acids are strong and some are weak.

→ The reaction between an acid and a base is called Neutralisation.

→ Antacids are used to treat indigestion.

→ Solution of baking soda (Sodium hydrogen carbonate) rubbed to treat the effects of insect bites.

→ The basicity of the soil is eliminated by the use of organic matter.

PSEB 7th Class Science Notes Chapter 5 Acids, Bases and Salts

→ The acidity of the soil is treated with bases like a quick (calcium oxide) or slaked lime (Calcium hydroxide).

→ Waste products from factories should be released into the water only after treatment with basic substances.

→ Acids: Substances that have a sour taste and which react with blue litmus solution to make its color red are called acids.

→ Bases (Alkali): Substances that have a bitter taste and which react with red litmus solution to make it blue are called bases.

→ Neutralisation: The reaction between an acid and an alkali is called neutralisation.

→ Neutral solution: A solution that is neither acidic in nature nor alkaline in nature is called a neutral solution or solution which does not change the color of the indicator is called a neutral solution.

→ Indicators: Indicators are substances that show different colours by reacting with different acids, salts, and bases.

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