Question

Iodine fluoride gas (IF) decomposes to gaseous iodide (I₂) and fluoride (F₂) at a high temperature. If K_p at this high temperature is 19.7, determine the equilibrium partial pressure of IF gas if its initial concentration was 0.306 atm? Hint: You should write a balanced chemical equation for the reaction described.

Question 6 options:

	0.153 atm
	0.0689 atm
	0.168 atm
	0.0310 atm
	0.138 atm

Answer 1

SOLUTION

We have the balanced chemical reaction is

2IF    $\rightleftharpoons$ I₂ + F₂

Initial concentration   0.306 atm 0 0

equillibrium concentration 0.306 - 2x    x x

K_p = [I₂ ][F₂]/[IF]² = 19.7

x*x / ( 0.306 - 2x )² = 19.7

x² = 19.7 (0.0937 + 4x² - 1.224x)

   x² = 1.845 + 78.8 x² - 24.11x

77.8 x²  - 24.11x +1.845 = 0

Solving the quadratic equation. we will get the value of x

x = 0.138

Then equillibrium partial pressure of IF = 0.306 - 2x atm = 0.306 - 2* 0.138 = 0.030 atm

So, the correct option is 0.0310 atm Answer