The equilibrium constant is equal to 5.00 at 1300 K for the reaction: 2 SO2(g) + O2(g) ⇌ 2 SO3(g). If initial concentrations are [SO2] = 1.20 M, [O2] = 0.45 M, and [SO3] = 1.80 M, the system isA) at equilibrium.
B) not at equilibrium and will remain in an unequilibrated state.
C) not at equilibrium and will shift to the left to achieve an equilibrium state.
D) not at equilibrium and will shift to the right to achieve an equilibrium state.

Option A is correct. The system is at equilibrium

Explanation:

Step 1: Data given

Kc at 1300 K = 5.00

Initial concentration of SO2 = 1.20 M

Initial concentration of O2 = 0.45 M

The concentration of SO3 = 1.80 M

When Q=K, the system is at equilibrium and there is no shift to either the left or the right.

When Q<K, there are more reactants than products. As a result, some of the reactants will become products, causing the reaction to shift to the right.

When Q>K, there are more products than reactants. To decrease the amount of products, the reaction will shift to the left and produce more reactants.

Step 2: The balanced equation

2 SO2(g) + O2(g) ⇌ 2 SO3(g)

Step 3: Calculate Q

Q = [SO3]² / [O2][SO2]²

Q = 1.80²/0.45*1.20²

Q = 5.00

Q = Kc

This means , the system is at equilibrium and there is no shift to either the left or the right.

Option A is correct.