ECAT Pre Engineering Chemistry Chapter 8 MCQ Test With Answer

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 the above reaction the relationship b/w k_c and k_p will be :

• K_p = K_cRT

  A

• Kp = K_c(RT)_-1

  B

• K_p = K_c(RT)_-2

  C

• K_c = K_p

  D

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

• 450°C A
• 250°C B
• 850°C C
• 1000°C D

An aqueous solution is neutral when its

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

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

• KC = KP A
• Kp = KcRT B
• Kp = kc(RT)^-2 C
• Kp = Kc(RT)^-1 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

• 4 mole per dm³ A
• 2 mole per dm³ B
• 0.33 mole per dm³ C
• 0.67 mole per dm³ 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

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

Which one of the following has no units of its K_cvalue

• 
  A
• 
  B
• 
  C
• 
  D

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

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

pH of the human blood which is essentially maintained constant due to carbonates, biocarbonates, phosphates etc., is

• 7.00 A
• 7.25 B
• 7.35 C
• 7.47 D

A solution of NaOH has pH = 13, then concentration of NaOH is

• 10^-13M A
• 10¹³M B
• 10^-1M C
• 10⁺¹M D

• 0.12 A
• 0.50 B
• 0.25 C
• 4.00 D

When a weak acid is dissolved in water or a weak base dissolved in water, then in both cases the conjugate acid base pair is produced. The ionization constants K_aand K_bof a pair are related with each other as

• K_a= K_b A
• K_a. K_b= K_w B
• K_a. K_w= K_b C
• K_b. K_w= K_a D

The relation between Kc and Kp is

• 
  A
• 
  B
• 
  C
• 
  D

A reaction is reversible because :

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

Law of mass action states that rate of chemical reaction is directly proportional to the product of active masses of the reactants. The term active mass means

• Mass in grams converted to products A
• Number of moles B
• Number of moles per dm³of reactants C
• Total pressures of the reactants 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

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

Which of the following in an example of reversible reaction

• 
  A
• 
  B
• 
  C
• 
  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

• 
  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

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

• Forward reaction is favoured A
• Backward reaction is favoured B
• No effect C
• None of the above D