The equilibrium constant (k p) for the interconversion of pcl 5 and pcl 3 is 0.0121: pcl 5 (g) pcl 3 (g) cl 2 (g) a vessel is charged with pcl 5, giving an initial pressure of 0.123 atm. at equilibrium, the partial pressure of pcl 3 is atm.

0.0386 atm

Explanation:

For a reversible reaction, the equilibrium is the point where the velocity of the formation of the products is equal to the velocity of the formation of the reactants. In equilibrium, the concentrations, or the partial pressures, don't change.

The equilibrium constant (K) may be calculated from de molar concentration (Kc) or from de partial pressure (Kp), which are, for a common reaction:

aA + bB ⇆ cC + dD

The partial pressure is given only for gases and the molar concentration for gases and liquids. So, for the reaction give:

PCl₅(g) ⇆ PCl₃(g) + Cl₂(g)

0.123 0 0 Initial

-x +x +x Reacted

0.123-x x x Equilibrium

Supposing x<<0.123 :

x² = 0.123x0.0121

x² = 1.4883x10⁻³

x = √1.4883x10⁻³

x = 0.0386 atm

Which is the partial pressure of PCl₃.

the correct answer is a