Question

A sealed 1.0L flask is filled with 0.500 mols of I_2 and 0.500 mols of Br_2. When the container achieves equilibrium the equilibrium constant is 1.10x10^{-2}. What is the equilibrium concentration of the product, IBr?

Answer 1

Answer:

[IBr] = 0.049 M.

Explanation:

Hello there!

In this case, according to the balanced chemical reaction:

$I_2+Br_2\rightarrow 2IBr$

It is possible to set up the following equilibrium expression:

$K=\frac{[IBr]^2}{[I_2][Br_2]} =0.0110$

Whereas the the initial concentrations of both iodine and bromine are 0.50 M; and in terms of $x$ (reaction extent) would be:

$0.0110=\frac{(2x)^2}{(0.50-x)^2}$

Which can be solved for $x$ to obtain two possible results:

$x_1=-0.0277M\\\\x_2=0.0245M$

Whereas the correct result is 0.0245 M since negative results does not make any sense. Thus, the concentration of the product turns out:

$[IBr]=2x=2*0.0249M=0.049M$

Regards!