Class 11

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

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

51. The pH of 0.005M codeine ( ) solution is 9.95. Calculate its ionization constant and pKb. 52. What is the pH of 0.001 M aniline solution? The ionization constant of aniline can be taken from Table 7.7. Calculate the degree of ionization of aniline in the solution. Also calculate the ionization constant of the … 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

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

Exercise 14.5 1. Show that the statement “If is a real number such that then is 0” is true by (i) direct method (ii) method of contradiction (iii) method of contrapositive. Ans. The given compound statement is of the form “if then ”. R such that (i) Direct method: If we assume that is true … Read more

Hydrogen  1. Justify the position of hydrogen in the periodic table on the basis of its electronic configuration. 2. Write the names of isotopes of hydrogen. What is the mass ratio of these isotopes? 3. Why does hydrogen occur in a diatomic form rather than in a monoatomic form under normal conditions? 4. How can … Read more

Miscellaneous Exercise 1. Write the negation of the following statements: (i) For every positive real number , the number is also positive. (ii) All cats scratch. (iii) For every real number , either or (iv) There exists a number such that Ans. (i) There exists a positive real number such that is not positive. (ii) … 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 15.1 Find the mean deviation about the mean for the data in Exercises 1 and 2. 1. 4, 7, 8, 9, 10, 12, 13, 17 Ans. Mean of the given data Mean deviation about mean = = = 3 2. 38, 70, 48, 40, 42, 55, 63, 46, 54, 44 Ans. Mean of 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 15.2 Find the mean and variance for each of the data in Exercises 1 to 5. 1. 6, 7, 10, 12, 13, 4, 8, 12 Ans. Given: = 6, 7, 10, 12, 13, 4, 8, 12 = 6 + 7 + 10 + 12 + 13 + 4 + 8 + 12 = 72 … 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