Answer
(a) $$K_c = \frac{[NO_2]^2}{[NO]^2[O_2]}$$
(b) $$K_c = \frac{[Zn^{2+}]}{[Ag^+]^2}$$
(c) $$K_c = \frac{[OH^-]^2}{[C{O_3}^{2-}]}$$
Work Step by Step
1. The $K_c$ expression follows this pattern:
$aA + bB \leftrightharpoons cC + dD$
$$K_c =\frac{[Products]}{[Reactants]} = \frac{[C]^c[D]^d}{[A]^a[B]^b}$$
Where solids and pure liquids do not appear on the expression.
(a) $$K_c = \frac{[NO_2]^2}{[NO]^2[O_2]}$$
(b) $$K_c = \frac{[Zn^{2+}]}{[Ag^+]^2}$$
(c) $$K_c = \frac{[OH^-]^2}{[C{O_3}^{2-}]}$$
