ECAT Pre Engineering Chemistry Chapter 8 MCQ Test With Answer

• 0.02 A
• 0.2 B
• 50 C
• 25 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

• 
  A
• 
  B
• 
  C
• 
  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

• 0.5 A
• 4.0 B
• 2.5 C
• 0.25 D

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

Units of Kw are

• Mole dm^-3 A
• Mole²dm^-3 B
• Mole²dm^-6 C
• Mole²dm^-3 D

In exothermic reversible reaction increase in temperature shift the equilibrium to :

• Remains unchanged. A
• Product side. B
• Reactant side. C
• None of above. D

• 4 mole per dm³ A
• 2 mole per dm³ B
• 0.33 mole per dm³ C
• 0.67 mole per dm³ D

N₂3H₂⇌ 2NH₃

_{Which of the following change will favorthe formation of more}NH₃at equilibrium in above reaction :

• By adding NH_3. A
• By removingH_2. B
• By decreasing pressure. C
• By increasing pressure. D

At certain temperature, 50% of HI is dissociated into H₂and I₂the equilibrium constant is

• 1.0 A
• 3.0 B
• 0.5 C
• 0.25 D

Which of the following favours the reverse reaction in chemical equilibrium?

• Increasing the concentration of the reactant A
• Removal of the least one of the products at regular intervals B
• Increasing the concentration of one or more of the products C
• None of these D

Almost forward reaction is complete when value of k_{c :}

• Neither larger nor very small. A
• Very small. B
• Very large. C
• Negligible. D

• 
  A
• 
  B
• 
  C
• 
  D

Hydrogen gas and iodine vapours combine to form Hl at 425°C, the same composition of mixture is present if we start with decomposition of Hl. It suggests

• A static equilibrium A
• Law of mass action B
• A dynamic equlibrium C
• Irreversible reaction D

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

The rate of forward reaction is two times that of the reverse reaction at a given temperature and identical concentration, K equilibrium is

• 0.5 A
• 1.5 B
• 2.5 C
• 2.0 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

• Introduction of an inert gas at constant volume A
• Introduction of PCl₃(g) at constant B
• Introduction of PCl₅(g) at constant volume C
• Introduction of Cl₂at constant volume D

For the above reaction the relationship b/w k_c and k_p will be :

• K_p = K_cRT

  A

• Kp = K_c(RT)_-1

  B

• K_p = K_c(RT)_-2

  C

• K_c = K_p

  D

Whenever a week base is dissolved in water, it give its conjugate acid. similarly a weak acid in water produces its conjugate base. This conjugate acid-base pair concept is stated by

• Law of mass action A
• Le-charlier's principle B
• Common ion effect C
• Lowery Bronsted concept D

• Decrease in temperature favour more dissolution of the salt A
• Increase in temperature favour more dissolution of the salt B
• Lowering pressure favour more dissolution of the salt C
• Increasing pressure favour more dissolution of the salt D

An aqueous solution is neutral when its

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

In an exothermic reaction, a 10° rise in temperature will

• Decrease the value of equilibrium constant A
• Double the value of K_c B
• Not produce any change in K_c C
• Produce some increase in K_c 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

The optimum conditions of temperature and pressure to get maximum NH₃form N₂and H₂gases is

• 2000°C and 10 atmosphere A
• 0°C and 1 atmosphere B
• 400°C and 200-300 atmosphere C
• 200°C and 100 atmosphere 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

• 
  A
• 
  B
• 
  C
• 
  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

N₂ +3H₂⇌ 2NH_{3 + Heat for above equation, themaximum product will be obtained at :}

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