The gas-phase reaction 2 HI(g) ⇌ H (g) + I (g) follows the rate laws Rate Rate A…
CHEMISTRY · Multi-part · CBSE · Chemistry · Chemical Kinetics · Chemical Kinetics
Problem
The gas-phase reaction
2 HI(g) ⇌ H2(g) + I2(g)
follows the rate laws
Rateforward∝[HI]2
Ratereverse∝[H2][I2]
A chemist mixes the three gases in a rigid 2.00 L container at 500 K, obtaining the initial concentrations shown in the table.
Species Initial concentration / mol L−1
HI 0.40
H2 0.10
I2 0.05
(a) Using the proportional rate laws, calculate the initial ratio RatereverseRateforward. Show your reasoning.
(b) Based on the ratio obtained in part (a), identify the direction of the net conversion immediately after mixing. Justify your answer in terms of the relative magnitudes of the two opposing rates.
(c) Indicate which species’ concentration will begin to increase first and which will begin to decrease first. Explain your choices using the stoichiometry of the reaction and the direction found in part (b).