Question: Consider the reaction between sulfur dioxide and nitrogen dioxide: SO2(g) + NO2(g) <--> SO3(g) + NO(g)?
Kc= 8.8 at 1000K

Given the following concentrations, predict the direction in which the reaction will proceed and explain:
a) [SO2] =64.0 M, [NO2]= 12.4M, [SO3]= 18.5 M, and [No] =87.5 M  Edit

Answer: [SO3] * [NO]
--------------------- = Kc = 8.8 (given)
[SO2] * [ NO2]

putting the numerical values of concentrations of each reactants and products we get,
[18.5] * [87.5]
------------------------ = 2.03
[ 64] * [ 12.4]

2.03 is much lower than 8.8. so if we would able to high the numerical values in the numerator and low the numerical values of denominators, then Kc will increase. To do so, the concentrations of products have to increase the concentrations of reactants have to decrease. That means the reaction SO2(g) + NO2(g) <--> SO3(g) + NO(g) will shift to right.  Edit