The data below refer to the following reaction: 2NO(g) + Br₂(g) ⇌ 2NOBr(g) $\begin{array}{lccc} \text { Concentration (M) } & [\mathrm{NO}] & \left[\mathrm{Br}_{2}\right] & {[\mathrm{NOBr}]} \ \hline \text { Initial } & 2.5 & 5.0 & 1.0 \ \text { Equilibrium } & 2.0 & - & - \end{array}$ Find the concentration of NOBr when the system reaches equilibrium.

Question

Quizplus · Accepted Answer

The concentration of NOBr at equilibrium can be determined using the equilibrium constant expression, Kc = [NOBr]2/([NO]2[Br2]).

We can use the initial and equilibrium concentrations of NO and Br2 to determine the equilibrium concentration of NOBr. Let x be the concentration of NOBr at equilibrium.

Initial concentrations: 
[NO] = 1.0 M 
[Br2] = 0.5 M 
[NOBr] = 0 M

At equilibrium: 
[NO] = 0.8 M 
[Br2] = 0.2 M 
[NOBr] = x

Using the equilibrium constant expression: 
Kc = [NOBr]2/([NO]2[Br2]) 
1.8 = x2/(0.8)2(0.2)

Solving for x, we get: 
x = 1.5 M

Therefore, the concentration of NOBr at equilibrium is 1.5 M, which corresponds to choice C.

The Data Below Refer to the Following Reaction: 2NO(g) Find the Concentration of NOBr When the System Reaches Equilibrium