Chemistry

Problem

The following equilibrium mixture was a yellow–orange colour, as it contained a mixture of orange

\text{Cr}_2\text{O}_7^{2-}

ions and yellow

\text{CrO}_4^{2-}

ions.

\text{Cr}_2\text{O}_7^{2-}(\text{aq}) + \text{H}_2\text{O}(\text{l}) \rightleftharpoons 2\text{CrO}_4^{2-}(\text{aq}) + 2\text{H}^+(\text{aq})

What effect will adding alkali have on the colour of the mixture? Give a reason for your answer.