What is a test variable?

The equilibrium constant kc for the reaction 2 nocl(g) → 2 no(g) + cl2(g) is 0.453 at a certain temperature. a mixture of nocl, no, and cl2 with concentrations 1.30, 1.20, and 0.600 m, respectively, was introduced into a container at this temperature. which of the following is true? 1. no apparent reaction takes place. 2. [cl2] = 0.30 m at equilibrium. 3. nocl(g) is produced until equilibrium is reached. 4. [nocl] = [no] = [cl2] at equilibrium. 5. cl2(g) is produced until equilibrium is