$$\ce{2XY <--> X2(g) + Y2(g)} \hskip{2em} K_p=230$$

A certain gas, $\ce{XY(g)}$, decomposes as represented by the equation above. A sample of each of the three gases is put in a previously evacuated container. The initial partial pressures of the gases are shown in the table below.

$$\begin{array}{|c|c|} \hline \text{Gas} & \text{Initial Partial } \\ & \text{Pressure (atm)} \\ \hline \hline \ce{XY} & 0.010 \\ \hline \ce{X_2} & 0.20 \\ \hline \ce{Y_2} & 2.0 \\ \hline \end{array}$$

The temperature of the reaction mixture is held constant. In which direction will the reaction proceed?

Summary Submit Skip Question

Find the reaction quotient and compare it to $K_p$.

$$Q = \frac{[\ce{X_2}][\ce{Y_2}]}{[\ce{XY}]^2}$$ $$Q = \frac{(0.20)(2.0)}{0.010}$$ $$Q = \frac{.40}{0.0001}$$ $$Q = 4000$$

Since $Q \gt K_p$, the system must shift to the reactant side.