Question

A chemical engineer is studying the following reaction: 4 HCI (g)+02(g) → 2 H 20(g)+ 2 Cl 2(g) At the temperature the engineer picks, the equilibrium constant Kp for this reaction is 0.38. The engineer charges (fills") four reaction vessels with hydrogen chloride and oxygen, and lets the reaction begin. He then measures the composition of the mixture inside each vessel from time to time. His first set of measurements are shown in the table below. Predict the changes in the compositions the engineer should expect next time he measures the compositions reactioncompound expected change in pressure (no change) (no change) C (no change) (no change) (no change) (no change) (no change) C (no change) o (no change) C (no change) C (no change) (no change) ↑ increase 1.36 atm 7.14 atm 3.22 atm 7.69 atm 3.08 atm 7.57 atm 2.36 atm 6.83 atm 34 atm 8.21 atm 2.61 atm c 1% atm ↓decrease ↓ decrease C↓ decrease ↓ decrease ↓ decrease C ↓ decrease ↓ decrease ↓ decrease ↓ decrease C ↓decrease C ↓ decrease C ↓ decrease ↑ increase H,0 Cl2 HCI ↑ increase ↑ increase ↑ increase ↑ increase o f increase ↑increase ↑ increase ↑ increase H2o Cl2 HcI ., H20 Ci2 C

Answer 1

For the above question we have to measure the reaction quotient i.e

Q=$(P_{H_{2}O}^{2}*P_{Cl_{2}}^{4})/(P_{HCl}^{4}*P_{O_{2}})$ where P_x= Partial Pressure of X

If Q>K_P reaction will favour reactants means the reaction will go backwards and concentration or pressure of reactants will increase.

If Q=K_P there will be no change as the reaction is at equilibrium.

If Q<K_P reaction will favour products means the reaction will go forward and concentration or pressure of products will increase.

So

(a)Q=24.79, therefore

H2O and Cl2 will decrease and HCl and O2 will increase

(b) Q=0.38138 we can say that Q>Kp

So there will be slight increase in reactants and slight decrease in Product

(c)Q=0.38

There will be no change