ECAT Pre Engineering Chemistry Chapter 8 MCQ Test With Answer

• 0.5 A
• 4.0 B
• 2.5 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

The solubility of PbF₂is 2.6 x 10^-3mole dm^-3 then its solubility product is

• 2.6 x 10^-3 A
• 6.76 x 10^-6 B
• 5.2 x 10^-6 C
• 7.0 x 10^-8 D

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

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

The value of K_pis greater than K_cfor a gaseous reaction when

• Number of molecules of products is greater than the reactants A
• Number of molecules of reactants is greater than those of products B
• Number of molecules of reactants and products equal C
• Catalyst is added D

pH of 1 molar NaOH is

• 7 A
• zero B
• 14 C
• 10 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

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

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

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

• 3.0 A
• 2.7 B
• 2.0 C
• 1.5 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

• 0.02 A
• 0.2 B
• 50 C
• 25 D

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

Extent to H₂ + L₂ à2Hl can be increased by :

• Increasing temperature.

  A

• Increasing product.

  B

• Increasing pressure.

  C

• Adding a catalyst.

  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

• 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

• High temperature and low pressure A
• Low temperature and low pressure B
• Low temperature and high pressure C
• High temperature and high pressure 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 which system does the equilibrium constant, KC has units of concentration

• 
  A
• 
  B
• 
  C
• 
  D

If the difference of pKa values of the two acids is 2, then

• Acid with smaller pKa is 10 times stronger acid A
• Acid with greater pKa is 10 times stronger acid B
• Acid with smaller pKa is 100 times stronger acid C
• Acid with greater pKa is 100 times stronger acid D

The best buffer is prepared when molar concentrations of the salt and acid are equal, then its pH and pKa value are related

• pH = pKa A
• pH < pKa B
• pH > pKa C
• pH x pKa = 14 D

Which one of the following has no units of its K_cvalue

• 
  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

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

Which of the following in an example of reversible reaction

• 
  A
• 
  B
• 
  C
• 
  D

The ph of 10-3 mole dm-3 of an aqueous solution of H₂SO₄ is :

• 3.0

  A

• 2.7

  B
• 2.0 C

• 1.5

  D