if Qc is greater than Kc.reaction goes backward.and vice-versa.
HOW does that work?(just to remember this relation,im asking)

Asked by vicky Sekaran | 12th Nov, 2014, 10:39: PM

Expert Answer:

If Qc > Kc , then the reaction favors the reactants. This means that in the equation begin mathsize 11px style straight Q subscript straight c space equals space fraction numerator left square bracket straight C right square bracket to the power of straight c space left square bracket straight D right square bracket to the power of straight d over denominator left square bracket straight A right square bracket to the power of straight a space left square bracket straight B right square bracket to the power of straight b end fraction end style, the ratio of the numerator (the concentration or pressure of the products) to the denominator (the concentration or pressure of the reactants) is larger than that for Kc indicating that more products are present than there would be at equilibrium. Because reactions always tend toward equilibrium (Le Chatelier's principle), the reaction produces more reactants from the excess products, therefore causing the system to shift to the LEFT. This allows the system to reach equilibrium. 

Answered by Arvind Diwale | 13th Nov, 2014, 11:52: AM

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