When sodium hydroxide (NaOH) is added to the solution, the pH increases due to the presence of hydroxide ions (OH⁻), which react with hydrogen ions (H⁺) and decrease their concentration. This shift in equilibrium will favor the formation of chromate ions (CrO₄²⁻), causing the solution to become yellow as the concentration of Cr₂O₇²⁻ is reduced.
Chromate ions react according to the following equation, where the left side of the reaction is yellow and the right side is orange.
CrO42- + 2H+ ⇄ Cr2O72- + H2O
A student adds sodium hydroxide (NaOH) to the solution at equilibrium. In one to two sentences, describe and explain any changes to the solution that the student will observe.
1 answer