Question

The equilibrium expression for the the reaction:
H2(g) + I2(g) <--> 2HI(g) would be:
Group of answer choices

A. K = 2[HI] / [H2][I2]

B. K = [H2][I2] / [HI]2

C. K = [H2][I2] / 2[HI]

D. K = [HI]2 / [H2][I2]

Answer 1

Answer:

D.)   $K = \frac{[HI]^{2} }{[H_{2} ] [I_{2} ] }$

Explanation:

The general equilibrium expression looks like this:

$K = \frac{[C]^{c} [D]^{d} }{[A]^{a} [B]^{b} }$

In this expression,

-----> K = equilibrium constant

-----> uppercase letters = formulas

-----> lowercase letters = balanced equation coefficients

In this case, all of the reactants and products are gases, so they should all be included in the expression. The products are in the numerator and the reactants are in the denominator. This makes the correct expression:

$K = \frac{[HI]^{c}}{[H_{2} ]^{a} [I_{2} ]^{b} }$                                          <----- Insert formulas

$K = \frac{[HI]^{2}}{[H_{2} ] [I_{2} ] }$                                             <----- Insert coefficients