12th Chemistry - Book Back Answers - Unit 8 Ionic Equilibrium - English Medium Guides

  

 

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Tamil Nadu Board 12th Standard Chemistry - Unit 8: Book Back Answers and Solutions

    This post covers the book back answers and solutions for Unit 8 from the Tamil Nadu State Board 12th Standard Chemistry textbook. These detailed answers have been carefully prepared by our expert teachers at KalviTips.com.

    We have explained each answer in a simple, easy-to-understand format, highlighting important points step by step under the relevant subtopics. Students are advised to read and memorize these subtopics thoroughly. Once you understand the main concepts, you’ll be able to connect other related points with real-life examples and confidently present them in your tests and exams.

    By going through this material, you’ll gain a strong understanding of Unit 8 along with the corresponding book back questions and answers (PDF format).

Question Types Covered:

• 1 Mark Questions: Choose the correct answer, Fill in the blanks, Identify the correct statement, Match the following 
• 2 Mark Questions: Answer briefly 
• 3, 4, and 5 Mark Questions: Answer in detail

All answers are presented in a clear and student-friendly manner, focusing on key points to help you score full marks.

All the best, Class 12 students! Prepare well and aim for top scores. Thank you!

I. Multiple Choice Questions

1. Concentration of the Ag ⁺ ions in a saturated solution of Ag₂C₂O₄ is 2.24 x 10^-4mol L^-1  solubility product of Ag₂C₂O₄ is

a) 2.42x10^-8mol³L^-3

b) 2.66x10^-12 mol³L^-3

c) 4.5x10^-11 mol³L^-3

d) 5.619 x10-12 mol³L^-3

Answer Key:

d) 5.619 x10-12 mol³L^-3 

 

2. Following solutions were prepared by mixing different volumes of NaOH of HCl different concentrations. (NEET – 2018)

i.$\mathbf{60}\mathbf{ }\mathbf{m}\mathbf{L}\frac{\mathbf{M}}{\mathbf{10}}\mathbf{H}\mathbf{C}\mathbf{l}\mathbf{+}\mathbf{40}\mathbf{m}\mathbf{L}\frac{\mathbf{M}}{\mathbf{10}}\mathbf{N}\mathbf{a}\mathbf{O}\mathbf{H}$

ii.$\mathbf{55}\mathbf{m}\mathbf{L}\frac{\mathbf{M}}{\mathbf{10}}\mathbf{H}\mathbf{C}\mathbf{l}\mathbf{+}\mathbf{45}\mathbf{m}\mathbf{L}\frac{\mathbf{M}}{\mathbf{10}}\mathbf{N}\mathbf{a}\mathbf{O}\mathbf{H}$

iii.$\mathbf{75}\mathbf{m}\mathbf{L}\frac{\mathbf{M}}{\mathbf{5}}\mathbf{H}\mathbf{C}\mathbf{l}\mathbf{+}\mathbf{25}\mathbf{m}\mathbf{L}\frac{\mathbf{M}}{\mathbf{5}}\mathbf{N}\mathbf{a}\mathbf{O}\mathbf{H}$

iv.$\mathbf{100}\mathbf{m}\mathbf{L}\frac{\mathbf{M}}{\mathbf{10}}\mathbf{H}\mathbf{C}\mathbf{l}\mathbf{+}\mathbf{100}\mathbf{m}\mathbf{L}\frac{\mathbf{M}}{\mathbf{10}}\mathbf{N}\mathbf{a}\mathbf{O}\mathbf{H}$

pH of which one of them will be equal to 1?

a) iv

b) i

c) ii

d) iii

Answer Key:

d) iii

  

3. The solubility of BaSO4 in water is 2.42 x 10^-3 gL^-1 at 298K. The value of its solubility product (K_sp) will be (NEET -2018). (Given molar mass of BaSO₄ =233g mol^-1

a) 1.08 x 10^-14mol²L^-2

b) 1.08 x 10^-12 mol²L^-2

c) 1.08 x 10^-10 mol²L^-2

 d) 1.08 x 10^-8 mol²L^-2

Answer Key:

c) 1.08 x 10^-10 mol²L^-2 

 

4. pH of a saturated solution of Ca(OH)2 is 9. The Solubility product (K_sp) of Ca(OH)2

a) 0.5 x 10^-15

b) 0.25 x 10^-10

c) 0.125 x 10^-15

d) 0.5 x 10^-10

Answer Key:

a) 0.5 x 10^-15

  

5. Conjugate base for Bronsted acids H₂Oand HF are

a) OH^- and H₂FH⁺ , respectively

b) H₃O⁺ and F^- , respectively

c) OH^- and F^- , respectively

d) H₃O⁺ and H₂F⁺, respectively

Answer Key:

c) OH^- and F^- , respectively

 

6. Which will make basic buffer?

a) 50 mL of 0.1M NaOH+25mL of 0.1M CH₃COOH

b) 100 mL of 0.1M CH₃COOH+100 mL of 0.1M NH₄OH

c) 100 mL of 0.1M HCl+200 mL of 0.1M NH₄OH

d) 100 mL of 0.1M HCl+100 mL of 0.1M NaOH

Answer Key:

c) 100 mL of 0.1M HCl+200 mL of 0.1M NH₄OH

  

7. Which of the following fluro compounds is most likely to behave as a Lewis base?

a) BF3

b) PF3

c) CF4

d) SiF4

Answer Key:

b) PF3  

 

8. Which of these is not likely to act as Lewis base?

a) BF3

b) PF3

c) CO

d) F^-

Answer Key:

a) BF3  

 

9. The aqueous solutions of sodium formate, anilinium chloride and potassium cyanide are respectively

a) acidic, acidic, basic

b) basic, acidic, basic

c) basic, neutral, basic

d) none of these

Answer Key:

b) basic, acidic, basic

  

10. The percentage of pyridine (C₅H₅N) that forms pyridinium ion (C₅H₅NH) in a 0.10M aqueous pyridine solution  (K_b for C₅H₅N = 1.7 x 10^-9) is

a) 0.006%

b) 0.013%

c) 0.77%

d) 1.6%

Answer Key:

b) 0.013% 

  

11. Equal volumes of three acid solutions of pH 1, 2 and 3 are mixed in a vessel. What will be the H⁺ ion concentration in the mixture?

a) 3.7 x 10^-2

b) 10^-6

c) 0.111

d) none of these

Answer Key:

a) 3.7 x 10^-2

  

12. The solubility of AgCl (s) with solubility product 1.6 x 10^-10  in 0.1M NaCl solution would be

a) 1.26 x 10^-5M

b) 1.6 x 10^-9M

c) 1.6 x 10^-11M

d) Zero

Answer Key:

b) 1.6 x 10^-9M 

  

13. If the solubility product of lead iodide is 3.2 x 10^-8, its solubility will be

a) 2 x 10^-3M

b) 4 x 10^-4M

c) 1.6 x 10^-5M

d) 1.8 x 10^-5M

Answer Key:

a) 2 x 10^-3M 

  

14. MY and NY₃, are insoluble salts and have the same Ksp values of 6.2 x 10^-13 at room temperature. Which statement would be true with regard to MY and NY₃?

a) The salts MY and NY₃  are more soluble in 0.5M KY than in pure water

b) The addition of the salt of KY to the suspension of MY and NY₃  will have no effect

on their solubility’s

c) The molar solubilities of MY and NY₃  in water are identical

d) The molar solubility of MY in water is less than that of NY₃

Answer Key:

d) The molar solubility of MY in water is less than that of NY₃

  

15. What is the pH of the resulting solution when equal volumes of 0.1M NaOH and 0.01M HCl are mixed?

a) 2.0

b) 3

c) 7.0

d) 12.65

Answer Key:

d) 12.65

 

16. The dissociation constant of a weak acid is 1 x 10^-3. In order to prepare a buffer solution with a pH = 4, the $\raisebox{1ex}{$\mathbf{\left[}\mathbf{A}\mathbf{c}\mathbf{i}\mathbf{d}\mathbf{\right]}$}\!\left/ \!\raisebox{-1ex}{$\mathbf{\left[}\mathbf{S}\mathbf{a}\mathbf{l}\mathbf{t}\mathbf{\right]}$}\right.$ ratio should be

a) 4:3

b) 3:4

c) 10:1

d) 1:10

Answer Key:

d) 1:10

  

17. The pH of 10^-5M KOH solution will be

a) 9

b) 5

c) 19

d) none of these

Answer Key:

a) 9 

  

18. H₂PO₄^- the conjugate base of

a) PO₄^3-

b) P₂O₅

c) H₃PO₄

d) HPO₄^2-

Answer Key:

c) H₃PO₄

  

19. Which of the following can act as Lowry – Bronsted acid as well as base?

a) HCl

b) SO₄^2-

c) HPO₄^2-

d) Br^-

Answer Key: 

c) HPO₄^2-

  

20. The pH of an aqueous solution is Zero. The solution is

a) slightly acidic

b) strongly acidic

c) neutral

d) basic

Answer Key:

b) strongly acidic

  

21. The hydrogen ion concentration of a buffer solution consisting of a weak acid and its salts is given by

a) [H⁺]= $\frac{{\mathrm{K}}_{\mathbf{a}\mathbf{\left[}\mathbf{a}\mathbf{c}\mathbf{i}\mathbf{d}\mathbf{\right]}}}{\left[\mathrm{salt}\right]}$

b) [H⁺]=${\mathbf{K}}_{\mathbf{a}}\left[\mathbf{salt}\right]$

c) [H⁺]= ${\mathbf{K}}_{\mathbf{a}}\left[\mathbf{a}\mathbf{c}\mathbf{i}\mathbf{d}\mathbf{\right]}$

d) [H⁺]= $\frac{{\mathbf{K}}_{\mathbf{a}\mathbf{\left[}\mathbf{s}\mathbf{a}\mathbf{l}\mathbf{t}\mathbf{\right]}}}{\mathbf{\left[}\mathbf{a}\mathbf{c}\mathbf{i}\mathbf{d}\mathbf{\right]}}$

Answer Key:

a) [H⁺]= $\frac{{\mathrm{K}}_{\mathbf{a}\mathbf{\left[}\mathbf{a}\mathbf{c}\mathbf{i}\mathbf{d}\mathbf{\right]}}}{\left[\mathrm{salt}\right]}$

$\frac{ }{}$ 

22. Which of the following relation is correct for degree of hydrolysis of ammonium

acetate?

a) h=$\sqrt{\frac{{\mathbf{K}}_{\mathbf{h}}}{\mathbf{C}}}$

b) h=$\sqrt{\frac{{\mathbf{K}}_{\mathbf{a}}}{{\mathbf{K}}_{\mathbf{b}}}}$

c) h=$\sqrt{\frac{{\mathbf{K}}_{\mathbf{w}}}{{\mathbf{K}}_{\mathbf{a}}\mathbf{.}{\mathbf{K}}_{\mathbf{b}}}}$

d) h=$\sqrt{\frac{{\mathbf{K}}_{\mathbf{a}}\mathbf{.}{\mathbf{K}}_{\mathbf{b}}}{{\mathbf{K}}_{\mathbf{w}}}}$

Answer Key:

c) h=$\sqrt{\frac{{\mathbf{K}}_{\mathbf{w}}}{{\mathbf{K}}_{\mathbf{a}}\mathbf{.}{\mathbf{K}}_{\mathbf{b}}}}$

$\sqrt{\frac{{\mathbf{ }}_{}}{}}$ 

23. Dissociation constant of NH₄OH  is 1.8 x 10^-5 the hydrolysis constant of NH₄Cl would be

a) 1.8 x 10^-19

b) 5.55 x 10^-10

c) 5.55 x 10^-5

d) 1.80 x 10^-5

Answer Key:

b) 5.55 x 10^-10 

 

II. Short Answer Questions.

12th Chemistry

III. Long Answer Questions. 

12th Chemistry

IV. Exercise.   

12th Chemistry