Question

A chemist trying to synthesize a particular compound attempts two different synthesis reactions. The equilibrium constants for the two reactions are 23.3 and 2.2 X 10^4 at room temp. However, after 15minutes the chemist finds that the reaction with the smaller equilibrium constant produces more desired product. Explain how this might be possible.

I don't get it???
UsuAlly when the constant has a larger value it produces more produces making the reaction lie to the right at equilibrium. Why is the smaller constAnt producing more product????

Answer 1

What you say is true at equilibrium but no one said these reactions were at equilibrium. The activation energy may be so high that the more favorable reaction thermodynamically is so slow that it proceeds at a snails pace, even if it proceeds at all. The other reaction may not have that problem.
The next time you see or try to buy a diamond remember that diamonds are not favored; graphite is the stable form of carbon. Why? because of the activation energy required to get to the more stable form. So I need not fear that I will wake up tomorrow and my diamond will be graphite. That conversion will take place eventually but long after I've left this earth.