CBSE Class 7 Science Acids, Bases and Salts Worksheet with Solution by Expert Science Mam. Students of 7th Grade can solve this worksheet for extra preparation before exam. Private Teacher or Guardians of the Students can copy all the questions of this chapter and will match after solve their students.
Acids, Bases and Salts Class 7 Worksheet
Worksheet for Chapter No.5): – Acids, Bases and Salts
The following questions are important for your exams for 1 mark 2 mark or 5 marks. First solve the questions on your own and then saw the solution for understanding it better.
Practice worksheet for class 7
Section A
Q.1.) write the taste of following substances.
→ 1.) Lemon juice- sour in taste
2.) Sugar – sweet in taste
3.) Vinegar- sour in taste
4.) Amla – slightly bitter and sour in taste.
5.) Baking soda- bitter in taste
Q.2.) state the difference between acid and bases.
→ 1.) Acids are sour in taste while the basis are bitter in taste.
2.) Acid turns blue litmus paper red while base turns red litmus into blue.
Q.3.) Write the name of acid found in following substances.
→ 1.) Spinach – oxalic acid
2.) Grapes – tartaric acid
3.) Lemon – citric acid
4.) Ant’s sting – formic acid
Q.4.) What are the indicators ? write two names of natural indicators ?
→ Indicators are the type of substance that are used to test whether a substance is acidic or basic.
Naturally occurring indicators :-
1.) Turmeric
2.) China rose petals
Q.5.) Write the name of base found in following substance.
→ 1.) Soap – sodium hydroxide or potassium hydroxide
2.) Window cleaner – ammonium hydroxide
Q.6.) What are the neutral solutions?
→ The solutions which do not change the colour of it either red or blue litmus are known as neutral solution.
Q.7.) How to prepare lime water ?
→ To prepare lime water, take some water in a tumbler and add some
lime ( chuna ) into it. Stir the solution and keep it for some time. Pour a
little from the top and this is the lime water.
Q.8.) What is acid rain ?
→ Acid rain is the rain which contain acids because of carbon dioxide, Sulphur dioxide and nitrogen dioxide released into the air as a pollutants dissolve in Rain drops to form carbonic acid, sulphuric acid, and nitric acid respectively. Acid rain can cause damage to buildings, historical monuments, plants, and animals.
Q.9.) Explain neutralization reaction ?
→ When acid and base react together, the salt and water get formed. This reaction is known as neutralization reaction. When an acidic solution is mixed with a basic solution both the solutions neutralize the effect of each other. When an acid solution and the base solution mixed in suitable amount both the acidic nature of the acid and the basic nature of the base are destroyed. The resulting solution is a neither acidic nor basic. And this new substance is called as salt it may be acidic or basic or neutral in nature.
Hydrochloric acid + sodium hydroxide > sodium chloride+ water.
Q.10.) How neutralization is relevant to indigestion?
→ Our stomach contains hydrochloric acid. It helps us to digest food. But too much of acid in the stomach causes indigestion. Sometimes indigestion is painful. To relieve indigestion, we take an antacid such as milk of magnesia which contains magnesium hydroxide. It neutralizes the effect of excessive acid.
Q.11.) What is the source of litmus solution? What is the use of it?
→ The natural indicator litmus is extracted from lichens. It has purple colour in distilled water. When added to an acidic solution, it turns red and when added to a basic solution it turns blue. It is available in the form of solution are in the form of straps of paper known as litmus paper. Generally available in red and blue colour.
Q.12.) Among the acid , bases, and salts, which constitutes maximum percentage in a human body? Explain.
→ Among the acids bases and salts, Acids constitutes maximum percentage in a human body. As we know, our stomach produces hydrochloric acid for the digestion of food we intake. Our each and everybody cell contain deoxyribonucleic acid that is DNA. Proteins that build part of our cells are also made from acid called as amino acids. The facts in our body also contain fatty acids. Hence acids are found in more percentage in human body.
Q.13.) If Rubina performing some experiment, she dipped a red litmus paper in a solution, she found that the litmus paper remains red. What is the nature of the solution explain?
→ 1.) If red litmus paper dipped in a solution , and it remains red. Then there is no change in colour of the litmus paper.
2.) If red litmus dipped n a basic solution, it turns red litmus into blue.
3.) Rubina dipped a red litmus paper in a solution and it remains red so the solution is acidic in nature.
Q.14.) Why calamine solution is applied on the skin when an ant bites?
→ 1.) When an ant bites it injects the acidic liquid that is formic acid into the skin.
2.) Effect of the acid can be neutralized by rubbing moist baking soda that is sodium hydrogen carbonate or calamine solution which contains zinc carbonate on your skin.
Q.15.) What is the need of disposing factory waste before it allows to flow into water bodies?
→ The factory Waste contain acids. If they are allowed to flow into the water bodies the acids will kill fish and other organisms. The factory waste therefore neutralized by adding basic substances into it.
Q.16.) How soil should be treated after the use of chemical fertilizers?
→ 1.) The excessive use of chemical fertilizers Makes the soil acidic. Plants do not grow well when the soil is too acidic or basic.
2.) When the soil is too acidic , it is treated with bases like calcium oxide or calcium hydroxide.
3.) If the soil is basic then organic matter is added to it. Organic matter releases acids which neutralizers the basic nature of the soil.
Q.17.) What is the effect of distilled water on blue and red litmus paper?
→ Distilled water is a neutral in nature and hence it will not change the colour of the red litmus paper and the blue litmus paper.
Q.18.) Complete the following table.
→
SR.NO. |
Test Solution | Effect on turmeric solution |
1 | Lemon Juice |
No Change |
2 |
Vinegar | No Change |
3 | Baking Soda |
Change to red |
4 |
Common Salt | No Change |
5 | Lime Water |
Change to red |
6 |
Sugar |
No Change |