Consider the reaction represented by the equation below: H2(g) + 12(s) ⇌ 2HI(g) ∆H negative....

WAEC 1991

Consider the reaction represented by the equation below: H2(g) + 12(s) ⇌ 2HI(g) ∆H negative. Which of the following takes place when the temperature of the reaction vessel is decreased?

A. the gases condense
B. the yield of hydrogen increases
C. the concentration of the reactants remain constant
D. more of the hydrogen iodide decomposes
E. the yield of hydrogen iodide increases

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Correct Answer: Option E

Explanation

Decreasing the temperature in an exothermic reaction (where heat is released) shifts the equilibrium to favor the formation of products. In this case, it increases the yield of hydrogen iodide (HI) as the system seeks to produce more heat to counteract the temperature drop.

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