Discuss : i. Consider the following dissociation reaction : 2HI(g) ⇌ H2(g) + I2(g)
Discuss :
i. Consider the following dissociation reaction :
2HI(g) ⇌ H2(g) + I2(g)
Colour gas Violet coloured gas
The reaction is carried out in a closed vessel starting with hydrogen iodide.
ii. Now, let us start with hydrogen and iodine vapour in a closed container at a certain temperature.
H2(g) + I2(g) ⇌ 2HI(g)
1 Answers
i. Starting with hydrogen iodide :
Observations :
a. At first, there is an increase in the intensity of violet colour.
b. After certain time, the increase in the intensity of violet colour stops.
c. When contents in a closed vessel are analyzed at this stage, it is observed that reaction mixture contains the hydrogen iodide, hydrogen and iodine with their concentrations being constant over time.
Inference :
The rate of decomposition of HI becomes equal to the rate of combination of H2 and I2.
At equilibrium,
No net change is observed and both reactions continue to occur at equal rates.
Thus,
The reaction represents chemical equilibrium.
ii. Starting with hydrogen and iodine :
Observations :
a. At first, there is a decrease in the intensity of violet colour.
b. After certain time, the decrease in the intensity of violet colour stops.
c. When contents in a closed vessel are analyzed at this stage, it is observed that reaction mixture contains hydrogen, iodine and hydrogen iodide with their concentrations being constant over time.
Inference :
The rate of combination of H2 and I2 becomes equal to the rate of decomposition of HI. The reaction attains chemical equilibrium.