A Reaction Vessel Is Charged with Hydrogen Iodide, Which Partially

A reaction vessel is charged with hydrogen iodide, which partially decomposes to molecular hydrogen and iodine:
2HI (g) H₂(g) + I₂(g)
^{When the system comes to equilibrium at 425 °C, P}_HI ^{= 0.708 atm, and P}H₂ ^{= P}I₂
= 0) 0960 atm. The value of K_p at this temperature is .

A) 1.30 × 10^{- 2}
B) 6.80 × 10^{- 2}
C) K_p cannot be calculated for this gas reaction when the volume of the reaction vessel is not given.
D) 54.3
E) 1.84 × 10^{- 2}