ECAT Pre Engineering Chemistry Chapter 8 MCQ Test With Answer

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

• 32 A
• 64 B
• 16 C
• 4 D

• 1 A
• 10 B
• 5 C
• 0.33 D

The equilibrium constant in a reversible chemical reaction at a given temperature

• Depends on the initial concentration of the reactants A
• Depends on the concentration of one of the products at equilibrium B
• Does not depend on the initial concentration of rectants C
• It is characteristic of the reaction D

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

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

In a lime kiln, to get higher yield of CO₂, the measure that can be taken is

• To main high temperature A
• To pump out CO₂ B
• To remove Cao C
• To add more CaCO₃ D

• 
  A
• 
  B
• 
  C
• 
  D

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

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

• 
  A
• 
  B
• 
  C
• 
  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

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

• 3.0 A
• 2.7 B
• 2.0 C
• 1.5 D

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

pH and pKa of the buffer are related by Henderson equation which is

• 
  A
• 
  B
• 
  C
• 
  D

A large value of K_cmeans that at equilibrium :

• Less reactant and more products. A
• Reactants and product in same amounts. B
• More reactants and less products. C
• None of above. D

• Reversible reaction A
• Irreversible reaction B
• Spontaneous reaction C
• None of these 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

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

• The value of K_pfalls with rise in temperature A
• The value of K_pfalls with increasing pressure B
• Addition of V₂O₅catalyst increase the concentration of SO₃ C
• The value of K_pis equal to K_c D

A solution having pH = 4 its OH^-ion concentration in mole dm^-3is

• 1.0 x 10^-4 A
• 1.0 x 10^-10 B
• 1.0 x 10^-14 C
• 1 x 10⁰ D

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

I a chemical reaction equilibrium is said to have been established when :

• Rate of opposing reactions are equal. A
• Rate constants of opposing reactions are equal. B
• Opposing reactions stop. C
• Concentration of reactants and products are equal 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

• Moles^-2dm⁺⁶ A
• No units B
• Mole dm^-3 C
• Mole^-1dm^-3 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

strength of an acid can be determined by

• P^ka A
• P^kp B
• P^oH C
• P^kw D

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

The relation between Kc and Kp is

• 
  A
• 
  B
• 
  C
• 
  D