ECAT Pre Engineering Chemistry Chapter 8 MCQ Test With Answer

Ammonium carbonate when heated to 200°C gives a mixture of NH₃and CO₂vapour with a density of 13.0. What is the degree of dissociation of ammonia carbonate?

• 3/2 A
• 1/2 B
• 2 C
• 1 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

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

The solubility product of Ca(OH)₂is 6.5 x 10^-6. The concentration of OH^-ions is

• 1.175 x 10^-2 A
• 2.35 x 10^-2 B
• 3.25 x 10^-3 C
• 3.25 x 10^-4 D

A buffer solution of 0.1 molar HCOOH and 0.1 molar HCCONa has pH = 3.78 To is 0.01 molar HCl is added, then pH of the buffer solution becomes

• 2.78 A
• 4.78 B
• 3.78 C
• 3.70 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

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

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

H₂ + L₂ ----2Hl

In the above equilibrium system, if the concentration of reactants at 25°C is increased, the value K_C will :

• Remains Constant A
• Increases B
• Cecreases C
• Depends upon nature of reactans 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 equilibrium there is no further change in the concentration of Hl A
• At equilibrium concentration of l₂remains constant B
• At equilibrium concentration of H₂remains unaltered C
• At equilibrium the rate of formation of Hl is equal to the rate of decomposition of Hl 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

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

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

A reaction is reversible because :

• Products are stable. A
• Reactants are reactive. B
• Products are reactive. C
• Reactants re stable. D

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

Which of the following solution have zero pH

• 1 M HCI A
• MH₂SO₄ B
• 0.1 M HNO₃ C
• 1 M CH₃COOH D

In 1000 molecules of 0.001 M acetic acid the number of H⁺ions is 12.6, then its percentage of ionization is

• 1.33% A
• 1.26% B
• 12.6 C
• 1% D

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

• 0.5 A
• 4.0 B
• 2.5 C
• 0.25 D

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

• 
  A
• 
  B
• 
  C
• 
  D

Which of the following in an example of reversible reaction

• 
  A
• 
  B
• 
  C
• 
  D

pH of water is 7, if 0.01 M NaOH is added, than its pH is

• 12 A
• 14 B
• zero C
• 10 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

The solubility product of AgCl is 2.0 x 10^-3 mol² dm^-6 , The maximum concentration of Ag ion in the solution is :

• 2.0 x 10^-10 mol dm^-3

  A

• 1.41 x 10^-10 mol dm^-3

  B

• 1.0 x 10^-10 mol dm^-3

  C

• 4.0 x 10^-10 mol dm^-3

  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

Acetic acid is 1.33% ionized, In 1000 molecules of 0.1 M acetic acid the number of H⁺ions is

• 1.33 A
• 13.3 B
• 1.33 C
• 1 D