ECAT Pre Engineering Chemistry Chapter 8 MCQ Test With Answer

For which system does the equilibrium constant, kc has units of (concentration) ?

• N₂+3H_2-------2NH₃

  A

• H₂+L₂---------2HL

  B

• 2NO₂----------N₂O₄

  C

• 2HF--------H2+F₂

  D

• Temperature is increased A
• Pressure is increased B
• HCl is added C
• HCl is removed D

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

• Irreversible reactions A
• Reversible reactions B
• Opposing reactions C
• Spontaneous reactions D

pH of 1 molar NaOH is

• 7 A
• zero B
• 14 C
• 10 D

For what value ofK_{c almost forward reaction is complete :}

• K_{c =} 10³⁰

  A

• K_{c =} 10^-30

  B

• K_{c =} 0

  C

• K_{c =} 1

  D

ph of the buffer CH₃COOh + CH₃COONa is 3.76. If the mixture contains 1 molar acetic acid and 0.1 molar sodium acetate, then pKa of this buffer is

• 3.76 A
• 4.76 B
• 5.76 C
• 6.76 D

In a reversible chemical reaction having two reactants in equilibrium, if the concentration of the reactants are doubled then the equilibrium constant will

• Also be doubled A
• Be halved B
• Becomes one fourth C
• Remains the same D

Which one of the following is not a buffer

• H₂CO₃+ NaHCO₃solution A
• H₃PO₄+ NaH₂PO₄solution B
• Hl + Nal solution C
• NH₄OH + NH₄CI solution D

Extent to H₂ + L₂ à2Hl can be increased by :

• Increasing temperature.

  A

• Increasing product.

  B

• Increasing pressure.

  C

• Adding a catalyst.

  D

• Shift reaction toward forward direction A
• Shift reaction backward B
• Lower the value of K_c C
• No change in reaction D

In 1000 molecules of 0.001 M acetic acid the number of H⁺ions is 12.6, then its percentage of ionization is

• 1.33% A
• 1.26% B
• 12.6 C
• 1% D

• 0.073 A
• 0.147 B
• 0.05 C
• 0.026 D

N₂ + O₂ ⇌2NO

The unit of K_c for tis reaction will be:

• No unit

  A

• mol^-2 dm^-3

  B

• mol^-1 dm^-3

  C

• mol^-2 dm⁺³

  D

The rate of reaction :

• Remain same as reaction proceeds. A
• May decrease or increase as reaction proceeds . B
• Increase as reaction proceeds. C
• Decreases as reaction proceeds. D

1.1 mol of A is mixed with 2.2 mol of B and the mixture is kept in on litre flask till the equilibrium is reached. At equilibrium, 0.2 mol of C is formed. If the equilibrium reaction is A+2B 2C+D, the value of equilibrium constant is

• 0.002 A
• 0.004 B
• 0.001 C
• 0.003 D

2SO₂+ O₂⇌2SO₂H= 188KJ mole^-1

Which statement about following equilibrium is correct :

• The value ofK_pfalls with arise in temperature.

  A

• The value ofK_pis equal tok_c.

  B

• The value ofK_pfalls with the increase pressure.

  C

• Adding V₂O₅catalyst increase the equilibrium yield of Sulphur trioxide.

  D

• The value of K_pfalls with a rise in temperature A
• The value of K_pfalls with increasing pressure B
• Adding V₂O₅catalyst increase the equilibrium yield of sulphur trioxide equilibrium yield of sulphur trioxide C
• The value of K_pis equal to K_c D

For which system does the equilibrium constant. K_c has units of

• 
  A
• 
  B
• 
  C
• 
  D

• High temperature A
• Low temperature B
• Low pressure C
• High pressure D

A solution of NaOH has pH = 13, then concentration of NaOH is

• 10^-13M A
• 10¹³M B
• 10^-1M C
• 10⁺¹M D

K_avalue of HF acid is 6.7 x 10^-15the acid is a

• Weak acid A
• Moderately strong acid B
• Strong acid C
• Very weak acid D

The avtive mass of 64 g of HI in a two litre flask would be

• 2 A
• 1 B
• 5 C
• 0.25 D

A large value of K_cmeans that at equilibrium :

• Less reactant and more products. A
• Reactants and product in same amounts. B
• More reactants and less products. C
• None of above. D

• High temperature and low pressure A
• Low temperature and high pressure B
• Low temperature and low pressure C
• High temperature and high pressure D

Which one of the following has no units of its K_cvalue

• 
  A
• 
  B
• 
  C
• 
  D

The equilibrium constant in a reversible chemical reaction at a given temperature

• Depends on the initial concentration of the reactants A
• Depends on the concentration of one of the products at equilibrium B
• Does not depend on the initial concentration of rectants C
• It is characteristic of the reaction D

Law of mass action states that rate of chemical reaction is directly proportional to the product of active masses of the reactants. The term active mass means

• Mass in grams converted to products A
• Number of moles B
• Number of moles per dm³of reactants C
• Total pressures of the reactants D

The substance which increases rate of reaction but remains unchanged at the end of reaction is called :

• Catalyst. A
• Indicator. B
• Promoter. C
• Activator. D

strength of an acid can be determined by

• P^ka A
• P^kp B
• P^oH C
• P^kw D

In the particular reaction for the valueK_{c 1 x}10^-25which statement is correct :

• Almost forward reaction is completed. A
• Amount of reactant is negligible as compared to product. B
• Amount of product is negligible as compared to reactant. C
• Amount of product is equal to amount of reactant. D