Sulfur dioxide is a stable compound so its decomposition

Question

Sulfur dioxide is a stable compound so its decomposition into the elements is characterized by a very small equilibrium constant.

SO₂(g) ? S(s) + O₂(g), K = 1.0 × 10^-65 at 25^oC (rxn 2)

a) Does this value apply to K_p or K_c or both? Explain.

b) Suppose a 1.0 L container is loaded with 1.0 mol SO₂(g) and 0.15 mol S(s). What will be the concentrations of SO₂(g) and O₂(g) in the system at equilibrium? How many moles of S(s) will be found at equilibrium?