Final answer:
The equilibrium constant (Kc) for the reaction 2NOBr(g) ⇌ 2NO(g) + Br₂(g) at 25°C cannot be calculated with the information provided as we lack the equilibrium concentration for NO.
Step-by-step explanation:
The question asks for the equilibrium constant (Kc) for the reaction 2NOBr(g) ⇌ 2NO(g) + Br₂(g) at 25°C. To solve this, we must use the equilibrium concentrations of the reactants and products in the expression for Kc. For this type of reaction, the general form of the equilibrium constant expression is Kc = [Products]² / [Reactants]². Using the information given where NOBr and Br₂ have the number of moles of
1.25 and 8.5 x 10⁻⁵ at equilibrium with a sufficient amount of solid NO (since the NO is a solid, it is not included in the equilibrium expression), and the volume of the container is not given, we must assume it to be constant and thus the moles can represent the concentration ratio directly. Therefore, Kc can be calculated as follows: ([NO]²[Br₂]) / [NOBr]² = ([x]² x 8.5 x 10⁻⁵) / (1.25²), where 'x' is the equilibrium concentration of NO (which will be the same as the concentration of Br2 due to the stoichiometry of the reaction). Since we are not given the value of 'x', we cannot calculate the precise Kc value without additional information. Thus, for this question, we are unable to provide the right Kc value from the options given without making assumptions or having further data.