ECAT Pre Engineering Chemistry Chapter 8 MCQ Test With Answer

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

• 
  A
• 
  B
• 
  C
• 
  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

N₂ + O₂ ⇌2NO

The unit of K_c for tis reaction will be:

• No unit

  A

• mol^-2 dm^-3

  B

• mol^-1 dm^-3

  C

• mol^-2 dm⁺³

  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

Which one of the following has no units of its K_cvalue

• 
  A
• 
  B
• 
  C
• 
  D

A chemical reaction is in equilibrium when

• Formation of product is minimum A
• Reactants are completely transformed into products B
• Rates of forward and backward reactions are equal C
• Equal amounts of reactants and products are present D

• Favour the formation of N₂O₄ A
• Favour the decomposition of N₂O₄ B
• Not alter the equilibrium C
• Stop the reaction 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

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

• 0.5 A
• 4.0 B
• 2.5 C
• 0.25 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

• Low pressure A
• High pressure B
• High temperature C
• High concentration of SO₂ D

When H₂and I₂are mixed and equilibrium is attained, then

• Amount of HI formed is equal to the amount of H₂dissociated A
• HI dissociation stops B
• The reaction stops completely C
• None of these D

Which one of the following is a buffer

• HCI + NaCI solution A
• CH₃COOH + CH₃COONH₄solution B
• H₂SO₄+ CaSO₄solution C
• CH₃COOH + CH₃COONa 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

Ifk_cof a reaction productis verylarge, it indicates that equilibrium occurs :

• With the help of a catalyst. A
• With no forward reaction. B
• At a low product concentration. C
• At a high product concentration. D

• 0.12 A
• 0.50 B
• 0.25 C
• 4.00 D

The rate at which a substance reacts is directly proportional to its active mass and the rate of reaction is directly proportional to the product of the active masses of reacting substances, is called

• Law of conservation of energy A
• Le-Chateliers principle B
• Law of mass action C
• None of these D

A gas bulb is filled with NO₂gas and immersed in an ice bath at 0°C which becomes colourless after sometimes. This colourless gas will be

• NO₂ A
• N₂O B
• N₂O₄ C
• N₂O₅ 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

2SO₂ + O₂ ⇌ 2SO₂ H= 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 V₂O₅ catalyst increase the equilibrium yield of Sulphur trioxide.
  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

The state of equilibrium refers to

• State of rest A
• Dynamic state B
• Stationary state C
• State of inertness D

The relation between Kc and Kp is

• 
  A
• 
  B
• 
  C
• 
  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

• Pressure change A
• Temperature change B
• Concentration change C
• Catalyst D

The substance which increases rate of reaction but remains unchanged at the end of reaction is called :

• Catalyst. A
• Indicator. B
• Promoter. C
• Activator. 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

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

• K_p> K_c A
• K_c> K_p B
• K_p= K_c C
• None of these D