J.R. S. answered 03/26/22
Ph.D. University Professor with 10+ years Tutoring Experience
H₂ (g) + F₂ (g) ⇌ 2 HF (g)
5...........5.................0........Initial
-x..........-x..............+2x......Change
5-x.....5-x.................2x......Equilibrium
Kp = 0.450 = (PHF)2 / (PH2)(PF2)
0.450 = (2x)2 / (5-x)(5-x)
Solve for x using the quadratic formula
The equilibrium pressure of HF will be 2x