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#### Ionic Equilibrium - Two Marks Study Materials

12th Standard EM

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Chemistry

Time : 00:45:00 Hrs
Total Marks : 30
15 x 2 = 30
1. What are lewis acids and bases? Give two example for each.

2. Discuss the Lowery – Bronsted concept of acids and bases.

3. Indentify the conjugate acid base pair for the following reaction in aqueous solution
i) HS- (aq) + HF $\rightleftharpoons$ F-(aq) + H2S(aq)
ii) HPO2-+ SO32- $\rightleftharpoons$ PO43-+HSO3-
iii) NH4+ CO32-  $\rightleftharpoons$ NH3+HCO3-

4. Account for the acidic nature of HClO4. In terms of Bronsted – Lowry theory, identify its conjugate base.

5. When aqueous ammonia is added to CuSO4 solution, the solution turns deep blue due to the formation of tetramminecopper (II) complex, ${ [Cu({ H }_{ 2 }O)] }_{ (aq) }^{ 2+ }\rightleftharpoons 4{ NH }_{ 3 }(aq)\rightleftharpoons { [Cu{ ({ NH }_{ 3 }) }_{ 4 }] }_{ (aq) }^{ 2+ }$ among H2O and NH3 Which is stronger Lewis base.

6. The concentration of hydroxide ion in a water sample is found to be 2.5×10-6M. Identify the nature of the solution.

7. A lab assistant prepared a solution by adding a calculated quantity of HCl gas 250C o to get a solution with [H3O+]= 4$\times$10-5M. Is the solution neutral (or) acidic (or) basic.

8. Calculate the pH of 0.04 M HNO3 Solution.

9. Define solubility product

10. Calculate the concentration of OH- in a fruit juice which contains $2\times10^{-3}$ M, H3O+ ion. Identify the nature of the solution.

11. Calculate the pH of 0.001M HCl solution

12. Calculate pH of 10-7M HCl

13. The KW of a neutral solution is 10-12 at a particular temperature. What are its pH and pOH values?

14. Calculate the ionisation constant for the conjugate base of HF. Ionisation constant of HF at 298 K is 6.8 X 10-4

15. What are the limitations of Ostwald's dilution law?