Chapter 6 – Multiple Choice Questions

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Multiple Choice Questions:

l. When a rate of forward reaction is equal backward reaction, then the equilibrium established is called.

(i) Chemical equilibrium

(ii) Static equilibrium

(iii) Dynamic equilibrium

(iv) None of these

 

2. N2O4 <– –> 2NO2 is an example of

(i) Reversible reaction

(ii) Irreversible reaction

(iii) Spontaneous reaction

(iv) None of these

 

3. Reactions that proceed on both sides and never go to completion are called

(i) Irreversible reactions

(ii) Reversible reactions

(iii) Opposing reactions

(iv) Spontaneous reactions

4. The equilibrium coherent can be used to predict

(i) The direction of reaction

(ii) The extent of a reaction

(iii) The cited of changing conditions

(iv) All of the above

 

5. Alcohols and acids react to form water and

(i) Halides

(ii) Esters

(iii) Amines

(iv) Ketones

 

6. What factors will change the equilibrium state of a system?

(i) Temperature

(ii) Pressure

(iii) Volume

(iv) All of them

 

7. If a system at equilibrium is disturbed by some change. The system will shift so as to counteract the effect of the change. This is statement of

(i) Law of mass action

(ii) Law of conservation of energy

(iii) Le- Chateliers principle

(iv) None of these

 

8. A catalyst merely speeds up the attainment of equilibrium by lowering the

(i) Energy of activation

(ii) Entropy

(iii) Enthalpy

(iv) internal energy

 

9. Very small value of Kc indicates that the reaction is

(i) High yield

(ii) Low yield

(iii) Moderate yield

(iv) No yield

 

10. Very large value of Kc indicates that the reaction is

(i) Partially complete

(ii) Incomplete

(iii) Almost complete

(iv) Tends to complete

 

11. Increase of pressure has marked effect on

(i) N2 + O2 <====> NO

(ii) 2N2 + 3H2 <====> 2NH3

(iii) PCl5 <====> PC13 + C12

(iv) None of these

 

12. Le- chatelier’s principle is concerned with

(i) Catalysis

(ii) Photolysis

(iii) Photosynthesis

(iv) Chemical equilibrium

 

13. Considering the following reaction 2SO2 + O2 <====> 2SO3 ∆H = -ve. The yield of S03 will be maximum if

(i) Temperature is increased, pressure kept constant

(ii) Temperature is reduced, pressure increased

(iii) Temperature and pressure are both decreased

(iv) Temperature and pressure are both decreased

 

14. Given the equilibrium

PC15 (g) <====> PCl3(g)+ C12 (g) ∆H = +ve. The concentration of C12 at equilibrium will be increased by

(i) By lowering of temperature

(ii) Adding PC13 the mixture

(iii) Adding PC 15to the mixture

(iv) Increasing the pressure

 

15. What happens when a reaction is at equilibrium and more reactant is added?

(i) Equilibrium remains unchanged

(ii) Forward reaction rate increase

(iii) Reverse rate of reaction increase

(iv) None of these

16. AgC1 is _____ in water:

(i) Insoluble

(ii) Soluble completely

(iii) De- electrolysis

(iv) None of these

 

17. Solubility product is the product of concentration of

(i) +ve ions

(ii) -ve ions

(iii) both A and B

(iv) None of these

 

18. _______ in temperature favors the formation of product in case of exothermic reaction:

(i) Increase

(ii) Decrease

(iii) Constancy

(iv) None of these

 

19. Energy required in addition to the average energy of reactants to convert them into products is called.

(i) Potential

(ii) Kinetic

(iii) Activation

(iv) Excitation

 

20. The equation for the reversible reaction of acetic acid (aq):

(i) CH3COOH + C2 H5OH ———> CH3COOC2H5 + H2O

(ii) CH3COOH ———> CH3COO- + H+

(iii) CH3COOH ———> CH 3COO- + H+

(iv) CH3COOH + NaOH ———> CH 3COONa + H2O

 

21. Given a system in equilibrium an increase in the concentration of the products is always produce by a rise of temperature when reaction is:

(i) In the gas phase

(ii) Spontaneous

(iii) Endothermic

(iv) Catalysed

 

22. In the beginning of reaction

(i) Rate of reverse reaction is more than rate of forward reaction

(ii) Rate of forward reaction is less than rate or reverse reaction

(iii) Rate of reverse reaction is equal to zero

(iv) None of these

 

23. For the reaction 2HI <====> H2 + I2 the value of Kc = 0.0156 at 52 °C. when the cone of HI, H2 and I2 is 1.00 mol/ lit each then the reaction will proceed.

(i) Backward reaction

(ii) Forward reaction

(iii) Remain constant

(iv) None of these

 

24. In the reaction H2 (Q) 21(9) the

(i) Kp>Kc

(ii) Kp>Kc

(iii) Kp= Kc

(iv) Kp≠ Kc

 

25. Under which one of following sets of conditions may the highest concentration of ammonia at equilibrium be obtained from the following reaction:

N2 + 2H2 <=====> 2NH3 ∆ = -92 KJ mol‾1

 

Temperature Pressure Catalyst
(i) High High Present
(ii) High High Absent
(iii) High Low Absent
(iv) Low High Presence

 

26 The Le- Chatelier’s principle is not applicable to the reaction:

(i) 2SO2 + O2 <=====> 2SO3 ∆H = -ive

(ii) PCl5 + O2 <=====> PC13 + C12 ∆H = +ive

(iii) N2 + 3H2  <=====> 2NH3 ∆H = -ive

(iv) Fe + S <=====>FeS∆H = -ive

 

27. N2O4   <=====> NO2

At equilibrium state:

(i) Equal amount of each substance present at equilibrium state

(ii) PCL5 +O2 <=====> PCL3 +CL2 ∆H = +ve

(iii) N2 + 3H2  <=====> 2NH3 ∆H = -ive

(iv) Fe + S <=====>FeS∆H = -ive

 

28. N2   <=====> 2NO2

At equilibrium state:

(i) Equal amount of each substance present at equilibrium state

(ii) The composition of this mixture remains constant due to same rate of forward and reverse reaction

(iii) Reaction is complete in a forward direction

(iv) None of these

 

29. The solubility product of AgBr is reported to be 4 x 10 10-13, AgBr gets precipitated when 10-6 MAgNO3 is added to

(i) 4 x 10-7 molar KBr

(ii) 2x 10-7 molar KBr

(iii) 5x 10-7 molar KBr

(iv) 3x 10-7 molar KBr

 

30. Precipitation takes place when the product of ionic concentration exceeds its:

(i) Concentration

(ii) Ionic product

(iii) 5 x10-7 molar KBr

(iv) 3x 10-7 molar KBr

31. Calculate the Kc of the following reaction

A + B <====> 2C + D

If initial concentration of the reactant and product is

Conc. of A = 1 moles / lit Cone of B = 0.02 moles/ lit

Conc. of C = 0.1 moles / lit Cone of D =1 moles/ lit

(i) 1

(ii) 0.5

(iii) 0.1

(iv) 1.5

 

32. A+ B ———-> C

Equilibrium constant of the reaction Kc = 10

Concentration of A = 1, mole / dm³

Concentration of B = 1, mole / dm³

Concentration of C = 0.5. mole / dm³

(i) The creation will shift towards right

(ii) The reaction will shift towards left

(iii) Equilibrium has been established

(iv) Reaction is stopped

 

33. A saturated solution of B a SO4 at 25 degree Celsius contains 3.9 x 10-5 mole / liters of Ba +2 ions what is the Ksp of this salt?

(i) 3.9 x 10-5

(ii) 3.9 x 10-6

(iii) 2.1×10-7

(iv) 1.5 x 10-9

 

34. If the ionic product is less than the solubility product, the solution is?

(i) Super saturated

(ii) Unsalurated

(iii) Saturation

(iv) Homogenous solution

 

35. The value of Ksp of PbCrO4 1.8 X10-14 the concentration of Pb 2+ is 6. 25 X

10-5 and CrO4-2 is 1.125 x 10-8 for the reaction so the

PbCrO4 <=====> Pb+2CrO4-2

(i) Solution is unsalted

(ii) Solution is precipitated out

(iii) Solution is saturated

(iv) Reaction is stop http://trymobilespy.com

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