ECAT Pre Engineering Chemistry Chapter 8 MCQ Test With Answer

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

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

Product of concentration of ions raised to the power equal to the co-efficient of ions in balanced equation for saturated solution of a salt is called

• Ionic product A
• Equilibrium constant K_c B
• K_w C
• Solubility product (K_sp) D

• 0.02 A
• 0.2 B
• 50 C
• 25 D

K_bvalue of NH₄OH is 1.81 x 10^-5and its conjugate acid has K_a= 5.7 x 10^-10pKb of the base is 4.74, pKa of its conjugate acid is

• -4.74 A
• 4.74 B
• 10 C
• 9.26 D

Two moles of HI was heated in a sealed tube at 440°C till the equilibrium was reached. HI was found to be 22% decomposed. The equilibrium constant for dissociation is

• 0.282 A
• 0.0796 B
• 0.0199 C
• 1.99 D

• Reaction occurs at STP A
• Reaction is exothermic B
• Reaction is endothermic C
• Number of moles of production and reactant are same 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

Under what condition of temperature and pressure the formation of atomic hydrogen from molecular hydrogen will be favourd

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

Which of the following in an example of reversible reaction

• 
  A
• 
  B
• 
  C
• 
  D

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

• 
  A
• 
  B
• 
  C
• 
  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

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

• 1 A
• 10 B
• 5 C
• 0.33 D

The concentration of reactants is increased by x, then equilibrium constant K becomes

• ln K/x A
• K/x B
• K + x C
• K D

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

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

A chemical reaction A---------->B is said to be in equilibrium when :

• Rate of transformation of A to B is equal to B to A. A
• 50% reactant has been changed to B. B
• Conversion of A to B is 50% complete C
• Complete conversion of A to B has taken place. D

Law of mass action was given by :

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

An aqueous solution is neutral when its

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

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

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

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

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 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

In which of the following cases, the reaction goes farthest to completion

• K = 10³ A
• K = 10^-2 B
• K = 10 C
• K = 10⁰ 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

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

Units of Kw are

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