Question

2C2H2 (g) + 5 O2 (g) ---------> 4 CO2 (g) + 2 H2O (g) + heat 3. Which of the following is true about reaction when the concentration of O2 (g) is decreased? a. Equilibrium will shift to the left. b. Equilibrium will shift to the right. c. No effect on the equilibrium. d. Equilibrium constant will decrease. 4. Which of the following is true about reaction when the temperature is increased? a. Equilibrium will shift to the left. b. Equilibrium will shift to the right. c. No effect on the equilibrium. d. No effect on the equilibrium constant. 5. Which of the following is true about reaction when the pressure is increased by decreasing the volume of the reaction container? a. Equilibrium will shift to the left. b. Equilibrium will shift to the right. c. No effect on the equilibrium. d. No effect on the heat produced.

Answer 1

3.the concentration of O2 (g) is decreased

We will apply Le chateleier's Principle

Here , O2 is basically the reactant. Hence when the reactant is decrease, as per Le chatelier's principle the equilibrium will try to move in the direction where it can negate the change that has been brought to the system.

Since the reactant is reduced the equilibrium will shift in the backward direction that is the product will be converted back to reactant to compensate for the amount of reactant that has been reduced

Hence answer should be (a) Equilibrium will shift to the left

4.Temperature is increased

      The given reaction is exothermic. since the reaction has +heat on right hand side, which means that heat is released along with product. Now as temperature is increased, as per Le Chatelier's principle the equilibirum will try to negate the change . Since the temperature is increased more heat is supplied to the system. So in order to negate it, the equilibrium will move in backward direction. Since its exothermic reaction the temperature of reactant is lesser than that of product. Hence the equilibrium will go in backward direction

Hence answer is option (a) the equilibrium will shift to the left

5. Increasing the pressure of the system

As pressure of the system is increased, by Le Chatlelier's principle the equilibrium will try to negate this change. Now as pressure is increased, the collision between molecules will increase . In order to negate it, we must reduce the number of collisions. To this the equilibrium will move in a direction where there are lesser number of moles. Lesser the number of moles, lesser is the collision.

Since the product side has 6 total moles compared to 7 total moles on reaction side, the equilibrium will move in the forward direction to negate the effect on increase in pressure

Hence, correct answer should be (b) Equilibrium will shift to the right