CHEMICAL EQUILIBRIUM JEE

Which of the following are Lewis acids?

• PH₃ and BCl₃

• AlCl₃ and SiCl₄

• PH₃ and SiCl₄

• BCl₃ and AlCl₃

Species acting as both Bronsted acid and base is

• (HSO₄) ^–

• Na2CO3

• NH3

• OH-

What is the conjugate base of OH^–?

• O₂

• H₂O

• O^–

• O^2-

Which one of the following substances has the highest proton affinity?

• H₂S

• NH₃

• PH₃

• H₂O

When rain is accompanied by a thunderstorm, the collected rainwater will have a pH value

• slightly lower than that of rainwater without a thunderstorm

• slightly higher than that when the thunderstorm is not there

• uninfluenced by the occurrence of a thunderstorm

• which depends on the amount of dust in the air.

For the reaction, 2SO_2(g) + O_2(g) ⇌ 2SO_3(g), ∆H = -57.2 kJ mol^–1 and Kc = 1.7 × 10¹⁶ Which of the following statements is incorrect?

• The equilibrium will shift in the forward direction as the pressure increases.

• The addition of inert gas at constant volume will not affect the equilibrium constant.

• The equilibrium constant is large, suggestive of reaction going to completion and so no catalyst is required.

• The equilibrium constant decreases as the temperature increases.

20 mL of 0.1 M H₂SO₄ solution is added to 30 mL of 0.2 M NH₄OH solution. The pH of the resultant mixture is [pK_b of NH₄OH = 4.7]

• 9.4

• 9.0

• 5.0

• 5.2

The increase of pressure on ice water system at constant temperature will lead to

• no effect on that equilibrium

• a decrease in the entropy of the system

• a shift of the equilibrium in the forward direction

• an increase in the Gibbs energy of the system.

The pH of rain water is approximately

• 7.5

• 6.5

• 7.0

• 5.6

A vessel at 1000 K contains CO₂ with a pressure of 0.5 atm. Some of the CO₂ is converted into CO on the addition of graphite. If the total pressure at equilibrium is 0.8 atm, the value of K is

• 1.8 atm

• 3 atm

• 0.3 atm

• 0.18 atm