NCERT Solutions

16. Why does the following reaction occur? What conclusion about the compound (of which is a part) can be drawn from the reaction. 17. Consider the reactions: (a) (b) (c) (d) What inference do you draw about the behaviour of and from these reactions? 18. Balance the following redox reactions by ion-electron method: (a) (in … Read more

17. Compare the structures of . 18. What do you understand by the term ‘auto-protolysis’ of water? What is its significance? 19. Consider the reaction of water with and suggest, in terms of oxidation and reduction, which species are oxidized/reduced. 20. Complete the following chemical reactions. (i) (ii) (iii) (iv) (v) Classify the above into … Read more

Exercise 14.2 1. Write the negation of the following statements: (i) Chennai is the capital of Tamilnadu. (ii) is not a complex number. (iii) All triangles are not equilateral triangle. (iv) The number 2 is greater than 7. (v) Every natural number is an integer. Ans. (i) Negation of statement is: Chennai is not the … Read more

The s block elements  1. What are the common physical and chemical features of alkali metals? 2. Discuss the general characteristics and gradation in properties of alkaline earth metals. 3. Why are alkali metals not found in nature? 4. Find the oxidation state of sodium in 5. Explain why is sodium less reactive than potassium? … Read more

Exercise 14.3 1. For each of the following compound statements first identify the connecting words and then break it into component statements: (i) All rational numbers are real and all real numbers are not complex. (ii) Square of an integer is positive or negative. (iii) The sand heats up quickly in the sun and does … Read more

16. Starting with sodium chloride how would you proceed to prepare (i) sodium metal (ii) sodium hydroxide (iii) sodium peroxide (iv) sodium carbonate? 17. What happens when (i) magnesium is burnt in air (ii) quick lime is heated with silica (iii) chlorine reacts with slaked lime (iv) calcium nitrate is heated ? 18. Describe two … Read more

Exercise 14.4 1. Rewrite the following statements with “if-then” in five different ways conveying the same meaning. If a natural number is off then its square is also odd. Ans. (i) A natural number is odd implies that its square is odd. (ii) A natural is odd only if its square is odd. (iii) For … Read more

20. What happens when (a) Borax is heated strongly, (b) Boric acid is added to water, (c) Aluminium is treated with dilute NaOH, (d) is reacted with ammonia? 21. Explain the following reactions (a) Silicon is heated with methyl chloride at high temperature in the presence of copper; (b) Silicon dioxide is treated with hydrogen … Read more

Exercise 3.2 Find the values of other trigonometric functions in exercises 1 to 5. 1. lies in third quadrant. Ans. Given: [ lies in third quadrant] Now, 2. lies in second quadrant. Ans. Given: [ lies in second quadrant] Now, 3. lies in third quadrant. Ans. Given: [ lies in third quadrant] Now, 4. lies … Read more

Exercise 7.4 1. If find Ans. Given: 2. Determine if: (i) (ii) Ans. (i) Given: (ii) Given: 3. How many chords can be drawn through 21 points on a circle? Ans. There are 21 points on the circumference of a circle. Since one and only one chord can be drawn by joining 2 distinct points, … Read more

Exercise 11.1 In each of the following Exercises 1 to 5, find the equation of the circle with: 1. Centre (0, 2) and radius 2. Ans. Given: and Equation of the circle = 2. Centre and radius 4. Ans. Given: and Equation of the circle = 3. Centre and radius Ans. Given: and Equation of … Read more