Predict which of the following reactions will have appreciable concentration of rectants and products:
a. `Cl_(2)(g) hArr 2Cl(g), K_(c)=5xx10^(-39)`
b. `Cl_(2)(g)+2NO(g) hArr 2NOCl(g), K_(c)=3.7xx10^(8)`
c. `Cl_(2)(g)+2NO_(2)(g) hArr 2NO_(2)Cl(g), K_(c)=1.8`

Explanation

To determine which of the given reactions will have appreciable concentrations of reactants and products, we will analyze the equilibrium constant (Kc) values provided for each reaction.

### Step-by-Step Solution:

1. **Understanding Kc**:
The equilibrium constant (Kc) is a measure of the ratio of the concentrations of products to reactants at equilibrium. A large Kc value indicates that at equilibrium, the concentration of products is much greater than that of reactants, while a small Kc value suggests that the concentration of reactants is much greater than that of products.

2. **Analyzing Reaction (a)**:
...