Chemistry class IX Unit test-III Question paper

SUBJECT – CHEMISTRY

UNIT TEST - 3 CLASS – XI A                                                        MAXIMUM MARKS – 40

SECTION – A ( 1 M EACH)

1. If in a mixture where Qc = Kc is combined, then what happens?

(a) The reaction shifts towards products

(b) The reaction shifts towards reactants

(c) Nothing appears to happen, but forward and reverse are continuing at the same rate

(d) Nothing happens

 

2. Which of the following can act as both Bronsted Acid and a Bronsted Base? 

(i) NH4+(ii) HCO3-(iii) Cl-(iv) CO32—

 

3.In which of the following reactions, the equilibrium remains unaffected on Addition of small amount of argon at constant volume?

(i) H2 (g) + I2 (g) ⇌ 2HI (g)

(ii) PCl5 (g) ⇌PCl3 (g) + Cl2 (g)

(iii) N2 (g) + 3H2 (g) ⇌2NH3 (g)

(iv) The equilibrium will remain unaffected in all the three cases.

 

4. The Solubility of A2X3 is y mol/dm3.Its Solubility product is 

  (a) 6y 4 (b) 64y 4(c) 36 y 5 (d) 108y5

 

5. The properties which are independent of the amount of the substance contained in the system but depend upon the nature of the substance only are called

a). Extensive properties  b). Intensive properties     c). State properties     d). none

 

6. H2SO4 acts as a strong oxidizing agent. In which of the reaction, is it not acting as an Oxidizing agent?

(a) C + 2H2SO4→ CO2 + 2SO2 + 2H2O

(b) CaF2 + 2H2SO4→ CaSO4 + 2HF

(c) S + 2H2SO4→ 3SO2 + H2O

(d) Cu + 2H2SO4→ CuSO4 + SO2 + 2H2O

 

7. During a reaction of oxalic acid, potassium chlorate and sulphuric acid, the oxidation number of which of the element undergoes a maximum change

 (a) H     (b) S        (c) C                   (d) Cl

8. Identify disproportionation reaction

(i) CH4 + 2O2 → CO2 + 2H2O

(ii) CH4 + 4Cl2→ CCl4 + 4HCl

(iii) 2F2 + 2OH– → 2F– + OF2 + H2O

(iv) 2NO2 + 2OH–⎯→ NO2- + NO3– + H2O

9. The oxidation number of iron in Fe3O4 is 

(a) +2 (b) +3 (c) 8/3 (d) 2/3

10. Standard electrode potential of three metals X, Y and Z are -1.2V, +0.5V and -3.0V respectively. The reducing power of these metals will be 

(a) X>Y>Z (b) Y>Z>X (c) Y>X>Z (d) Z>X>Y

 

SECTION – B (2 M EACH)

11. Classify the following species into Lewis acids and bases. 

(a) OH- (b) F- (c) H+ (d) BCl3

12. For the following equilibrium, K =6.3 x 1014 at 1000 K.

NO (g)+O3—–>NO2(g) + O2(g) Both the forward and reverse reactions in the equilibrium are elementary bimolecular reactions. What is Kc for the reverse reaction?

13.Balance the following ionic equation by using ion electro method                                                                                                                              Cr2O7 2– (aq) + SO3 2– (aq) → Cr3+(aq) + SO42– (aq) (acidic medium)

SECTION – C (4 M EACH)

14. What are buffer solutions? Explain its types with example.

 

15. Identify the oxidizing and reducing agents in the following equations: 

(i) Fe + H2SO4→FeSO4 + H2 

(ii) H2 + Cl2 →2HCl 

(iii)MnO2 + 4HCl→MnCl2 + 2H2O + Cl2

(iv) H2S (g) +Cl2 (g) → 2HCl (g) +S (s)

 

16. Explain the followings 

(i) Salt Bridge & its function.

(ii) Electrochemical series

 

17. The concentration of hydrogen ion in a sample of soft drink is 3.8 × 10–3 M. what is its pH?

18. On the basis of Le Chatelier principle explain how temperature and pressurecan be adjusted to increase the yield of ammonia in the following reaction.

N2 (g) + 3H2(g) ⇌2NH3(g) ∆H = – 92.38 kJ mol–1

 

19. For a water gas reaction at 1000k, the standard Gibb’s free energy change is -8.1kJ/mol. Calculate the Value of equilibrium constant Kc, for the reaction.