ECAT Pre Engineering Chemistry Chapter 8 MCQ Test With Answer

K_bfor NH₄OH is 1.81 x 10^-5, then K_avalue of its conjugate base is

• 1.81 x 10⁺⁵ A
• 1.81 x 10^-9 B
• 5.5 x 10^-9 C
• 5.5 x 10^-10 D

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

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

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

• 
  A
• 
  B
• 
  C
• 
  D

Units of Kw are

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

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

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

• Kw A
• Kn B
• Ka C
• Kb 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

• [A] = [B] A
• [A] < [B] B
• [B] = [C] C
• [A] > [B] D

According to Le-Chatelier's principal, adding heat to a solid and liquid in equilibrium will cause the

• Amount of solid to decrease A
• Amount of liquid to decrease B
• Temperature to rise C
• Temperature to fall 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

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

• Moles per dm³ A
• Partial pressures B
• Number of moles C
• Mole fractions 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

pH of 1 molar NaOH is

• 7 A
• zero B
• 14 C
• 10 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

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

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

When the rate of formation of reactants is equal to the rate of formation of products, this is known as

• Chemical reaction A
• Chemical equilibrium B
• Chemical kinetics C
• None D

The relation between Kc and Kp is

• 
  A
• 
  B
• 
  C
• 
  D

Buffers having pH less than 7 are made

• Mixture of weak acid + salt of it with strong base A
• Mixture of weak acid + salt of it with weak base B
• Mixture of weak base + salt of it with strong acid C
• Mixture of weak base + salt of it with weak base D

On passing HCI gas through a saturated solution of commercial sodium chloride, pure crystals of NaCI are precipitated due to

• Increase in pH of the solution A
• Decrease in pH of the solution B
• Common ion effect C
• Increase in ionization of NaCl D

For which system does the equilibrium constant, KC has units of concentration

• 
  A
• 
  B
• 
  C
• 
  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

The correct relation b/wK_{c and}K_{p is :}

• K_p = K_c[P/N] ^Δn

  A

• K_{c =} K_p(RT) ^Δn

  B

• K_{p =} K_c(RT) ^Δn

  C

• K_{p =} K_c(RT) ^Δn

  D

When rate of forward reaction is equal to rate of backward reaction, then the equilibrium established is called

• Chemical equilibrium A
• Static equilibrium B
• Dynamic equilibrium C
• None of these D

Which one of the following has no units of its K_cvalue

• 
  A
• 
  B
• 
  C
• 
  D