Revision Notes and Video Lectures on Real Numbers for Class 10 Board Exam (Padhte Chalo, Badhte Chalo- Eckovation). Join Group Code 101010 to discuss your doubts with educators from IIT Delhi
- Unit-1 of Class X C.B.S.E contains only one chapter which is Real Numbers.
- It carries 06 marks of the question paper
- The following questions are the set of important questions from this chapter
- Click Here for Revision Notes and Video Lecture of the topic
Multiple Choice Questions :
1. What happens when a solution of an acid is mixed with a solution of a base in a test tube?
(i) The temperature of the solution increases
(ii) The temperature of the solution decreases
(iii) The temperature of the solution remains the same
(iv) Salt formation takes place
(a) (i) only (b) (i) and (iii)
(c) (ii) and (iii) (d) (i) and (iv)
2. An aqueous solution turns red litmus solution blue. Excess addition of which of the following solution would reverse the change?
(a) Baking powder
(c) Ammonium hydroxide solution
(d) Hydrochloric acid
3. During the preparation of hydrogen chloride gas on a humid day, the gas is usually passed through the guard tube containing calcium chloride. The role of calcium chloride taken in the guard tube is to
(a) absorb the evolved gas
(b) moisten the gas
(c) absorb moisture from the gas
(d) absorb Cl– ions from the evolved gas
4. Which of the following salts does not contain water of crystallisation?
(a) Blue vitriol
(b) Baking soda
(c) Washing soda
(d) Gypsum Acids, Bases and Salts
5. Sodium carbonate is a basic salt because it is a salt of
(a) strong acid and strong base
(b) weak acid and weak base
(c) strong acid and weak base
(d) weak acid and strong base
6. Calcium phosphate is present in tooth enamel. Its nature is
l (d) amphoteric
7. A sample of soil is mixed with water and allowed to settle. The clear supernatant solution turns the pH paper yellowish-orange. Which of the following would change the colour of this pH paper to greenish-blue?
(a) Lemon juice
(c) Common salt
(d) An antacid
8. Common salt besides being used in kitchen can also be used as the raw material for making
(i) washing soda
(ii) bleaching powder
(iii) baking soda
(iv) slaked lime
(a) (i) and (ii) (b) (i), (ii) and (iv)
(c) (i) and (iii) (d) (i), (iii) and (iv)
9. One of the constituents of baking powder is sodium hydrogencarbonate, the other constituent is
(a) hydrochloric acid
(b) tartaric acid
(c) acetic acid
(d) sulphuric acid
10. To protect tooth decay we are advised to brush our teeth regularly. The nature of the tooth paste commonly used is
11. Which of the following statements is correct about an aqueous solution of an acid and of a base?
(i) Higher the pH, stronger the acid
(ii) Higher the pH, weaker the acid
(iii) Lower the pH, stronger the base
(iv) Lower the pH, weaker the base
(a) (i) and (iii) (b) (ii) and (iii)
(c) (i) and (iv) (d) (ii) and (iv)
12. The pH of the gastric juices released during digestion is
(a) less than 7
(b) more than 7
(c) equal to 7
(d) equal to 0
13. Which of the following phenomena occur, when a small amount of acid is added to water?
(iv) Salt formation
(a) (i) and (ii) (b) (i) and (iii)
(c) (ii) and (iii) (d) (ii) and (iv)
Short Answer Questions
1. Match the acids given in Column (A) with their correct source given in Column (B)
Column (A) Column (B)
(a) Lactic acid (i) Tomato
(b) Acetic acid (ii) Lemon
(c) Citric acid (iii) Vinegar
(d) Oxalic acid (iv) Curd
2. Match the important chemicals given in Column (A) with the chemical formulae given in Column (B)
Column (A) Column (B)
(a) Plaster of Paris (i) Ca(OH)2
(b) Gypsum (ii) CaSO4.1/2 H2O
(c) Bleaching Powder (iii) CaSO4 .2H2O
(d) Slaked Lime (iv) CaOC12
3. What will be the action of the following substances on litmus paper?
Dry HCl gas, Moistened NH3 gas, Lemon juice, Carbonated soft drink, Curd, Soap solution.
4. Name the acid present in ant sting and give its chemical formula. Also give the common method to get relief from the discomfort caused by the ant sting.
5. What happens when nitric acid is added to egg shell?
6. A student prepared solutions of (i) an acid and (ii) a base in two separate beakers. She forgot to label the solutions and litmus paper is not available in the laboratory. Since both the solutions are colourless, how will she distinguish between the two?
7. How would you distinguish between baking powder and washing soda by heating? 38. Salt A commonly used in bakery products on heating gets converted into another salt B which itself is used for removal of hardness of water and a gas C is evolved. The gas C when passed through lime water, turns it milky. Identify A, B and C.
Multiple Choice Questions
1. (d) 2. (d) 3. (c) 4. (b) 5. (d) 6. (a) 7. (d)11. (c) 12. (b) 13. (c) 14. (d) 15. (a) 16. (b)
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