Chemistry

Problem

A solution containing 0.050 mol of

\text{Fe}^{3+}

was added to an equal volume of a solution containing 0.030 mol of

\text{SCN}^-

ions. On mixing, a blood-red solution of

[\text{FeSCN}]^{2+}

was formed according to the following equation:

\text{Fe}^{3+}(\text{aq}) + \text{SCN}^{-}(\text{aq}) \rightleftharpoons [\text{FeSCN}]^{2+}(\text{aq})

At equilibrium, the mixture contained 0.020 mol of

[\text{FeSCN}]^{2+}

ions. The total volume of the mixture was

0.50 \text{ dm}^3

. Calculate the equilibrium constant for the reaction.