ECAT Pre Engineering Chemistry Chapter 8 MCQ Test With Answer

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

0.1 MHCI has pH = 1.0, it is about 100 times stronger than acetic acid. Then pH of acetic acid will be

• 0.1 A
• 2.0 B
• 1.3 C
• 3.0 D

Extent to H₂ + L₂ à2Hl can be increased by :

• Increasing temperature.

  A

• Increasing product.

  B

• Increasing pressure.

  C

• Adding a catalyst.

  D

• Le-chatlier's principle A
• Only adding catalyst B
• Decreasing pressure C
• Decreasing temperature D

The rate at which a substance reacts is directly proportional to its active mass and the rate of reaction is directly proportional to the product of the active masses of reacting substances, is called

• Law of conservation of energy A
• Le-Chateliers principle B
• Law of mass action C
• None of these D

In a reversible reaction, two substances are in equilibrium. If the concentration of each one is reduced to half, the equilibrium constant will be

• Reduced to half of its original value A
• Doubled B
• Same C
• Reduced to one fourth its original value D

The rate of a chemical reaction is directly;y proportional to product of molar concentration of reaction substance it is called :

• Low of conservation of energy. A
• Law of mass action. B
• Rate law . C
• Active mass rule. D

A solution having pH = 4 its OH^-ion concentration in mole dm^-3is

• 1.0 x 10^-4 A
• 1.0 x 10^-10 B
• 1.0 x 10^-14 C
• 1 x 10⁰ D

A solution has pH = 0, its H⁺ion concentration is

• 1 x 10^-14 A
• 1 x 10¹⁴ B
• 1 x 10¹ C
• 1 D

The state of equilibrium refers to

• State of rest A
• Dynamic state B
• Stationary state C
• State of inertness D

• Pressure change A
• Temperature change B
• Concentration change C
• Catalyst D

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

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

The ionization constant of an acid is expressed in term of the following constant

• Kw A
• Kn B
• Ka C
• Kb 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

• Reversible reaction A
• Irreversible reaction B
• Spontaneous reaction C
• None of these D

N₂O₄⇌ 2NO₂

For the above reaction, which of the Following expression of K_c correct :

• Kc = [ N₂O₄]/[ NO ₂]²

  A

• Kc = [ N₂O₄]/ [NO ₂]

  B

• Kc = [ N₂O]²/[ N₂O ₄]

  C

• Kc = [ N₂O₄]/[ N O ₂]

  D

• Moles^-2dm⁺⁶ A
• No units B
• Mole dm^-3 C
• Mole^-1dm^-3 D

An aqueous solution is neutral when its

• pH = 14 A
• pH = zero B
• pH = 7 C
• Kw = 10^-7 D

The pH of 10^-3mole dm^-3of an aqueous solution of H₂SO₄is

• 3.0 A
• 2.7 B
• 2.0 C
• 1.5 D

Which of the following is a characteristic of a reversible reaction?

• It never proceeds to completion A
• It can be influenced by a catalyst B
• It proceeds only in the forward direction C
• Number of moles of reactants and products are equal D

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

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

I a chemical reaction equilibrium is said to have been established when :

• Rate of opposing reactions are equal. A
• Rate constants of opposing reactions are equal. B
• Opposing reactions stop. C
• Concentration of reactants and products are equal D

• The value of K_pfalls with rise in temperature A
• The value of K_pfalls with increasing pressure B
• Addition of V₂O₅catalyst increase the concentration of SO₃ C
• The value of K_pis equal to K_c D

An excess of aqueous silver nitrate is added to aqueous barium chloride and precipitate is removed by filtration. What are the main ions in the filtrate

• 
  A
• 
  B
• 
  C
• 
  D

If pH of buffer of 1 mole dm^-3of HCOOH + 0.1 mole dm^-3HCOONa having pKa = 3.78 is

• 1.78 A
• 2.78 B
• 3.78 C
• 4.78 D

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

1 mol of N₂O₄ was decomposed according to given equation in 1dm₃ container. At equilibrium x mole of N₂O₄ have dissociated. What is the value of K_C:

• 2x/(1-x)²

  A

• 4x²/(1-x)

  B

• 4x/(1-x)

  C

• 2x/(1-x)

  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

• Increases A
• Decreases B
• Remains same C
• Cannot be predicted D