9th Class Chemistry Chapter 9 Test09. Chemical Equlibrium

Q1. Multiple choice questions (Attempt all · 5 × 1 = 5)

1. Concentration of reactants and products at equilibrium remains unchanged if:
   1. concentration of any reactant or product is not changed
   2. temperature of the reaction is not changed.
   3. pressure or volume of the system is not changed.
   4. all of the above are observed.
2. Which is true about the equilibrium state?
   1. The forward reaction stops.
   2. The reverse reaction stops.
   3. Both forward and reverse reaction stop.
   4. Both forward and reverse reaction continue at the same rate.
3. Which of the following does not happen, when a system is at equilibrium state?
   1. forward and reverse reactions stop.
   2. forward and reverse rates become equal.
   3. concentration of reactants and products stop changing
   4. reaction continues to occur in both the directions.
4. In an irreversible reaction equilibrium is:
   1. established quickly
   2. established slowly
   3. never established
   4. established when reaction stops.
5. When a mixture of H₂(g) and I₂(g) is sealed in a flask and temperature is kept at 25°C, equilibrium is established: H₂(g) + I₂(g) ⇌ 2HI(g). Which substance(s) will be present in the equilibrium mixture?
   1. H₂ and I₂
   2. HI only
   3. H₂ only
   4. H₂, I₂ and HI