ECAT Pre Engineering Chemistry Chapter 8 MCQ Test With Answer

What happens when reaction is at equilibrium and more reactant is added :

• Forward reaction rate is increased. A
• Forward reaction rate is decreased. B
• Backward reaction rate is increased. C
• Equilibrium remains unchanged. D

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

• Equal volumes of N₂and H₂are reacting A
• Equal masses of N₂and H₂are reacting B
• The reaction has stopped C
• The same amount of ammonia is formed as is decomposed into N₂and H₂ 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

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

The relation between Kc and Kp is

• 
  A
• 
  B
• 
  C
• 
  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

• 8 A
• 4 B
• 9 C
• 3 D

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

A chemical reaction is in equilibrium when

• Formation of product is minimum A
• Reactants are completely transformed into products B
• Rates of forward and backward reactions are equal C
• Equal amounts of reactants and products are present D

Addition of solid NaHCO₃in water causes ionization of NaCHO₃its K_a= 4.7 x 10^-1. Then this solution has character

• Acidic A
• Very weakly basic B
• Alkaline C
• Neutral D

• Increase in concentration of 1 A
• Decrease in concentration of I₂ B
• Increase in temperature C
• Increase in total pressure D

• Favour the formation of N₂O₄ A
• Favour the decomposition of N₂O₄ B
• Not alter the equilibrium C
• Stop the reaction D

• 0.5 A
• 4.0 B
• 2.5 C
• 0.25 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

Law of mass action was given by :

• Guldberg and Waage. A
• Berkeley and Hartly. B
• Ramsay and Reyleigh. C
• Berthelot. 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

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

• 
  A
• 
  B
• 
  C
• 
  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

• Total pressure A
• Amount of A₂and B₂ B
• Temperature C
• Catalyst D

• Forward A
• Backward B
• Already in equilibrium C
• K_cis never less 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

• Initial concentration of acetic acid A
• Initial concentration of ethyl acetate B
• Equilibrium concentration of acetic acid C
• Equilibrium concentration of ethyl acetate D

The solubility product of AgCl is 2.0 x 10^-10mol²dm^-6The maximum concentration of Ag⁺ions in the solution is

• 2.0 x 10^-10mol dm^-3 A
• 1.41 x 10^-5mol dm^-3 B
• 1.0 x 10^-10mol dm^-3 C
• 4.0 x 10^-20mol dm^-3 D

The rate of which the reaction proceeds is directly proportional to the product of the active masses of the reactants is according to

• Law of mass action A
• Le Chateliers principle B
• Equilibrium law C
• Law of constant proportion 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

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

Chemical equilibrium involving reactants and products in more than one phase is called

• Static A
• Dynamic B
• Homogeneous C
• Heterogeneous D