Question

Use the equation showing the dissociation of iron thiocyanate in water to answer the question.

FeSCN2+(aq) ⇄ Fe3+(aq) + SCN–(aq)

In solution, FeSCN2+ ions are red, Fe3+ ions are pale yellow, and SCN– ions are colorless.

Given that iron ions bind with hydroxide ions to produce solid Fe(OH)3, which statement about the solution is correct?

(1 point)

Increasing the pH will remove Fe3+ ions and cause the solution to become more red.

Increasing the pH will release Fe3+ ions and cause the solution to become more yellow.

Decreasing the pH will remove Fe3+ ions and cause the solution to become more yellow.

Decreasing the pH will release Fe3+ ions and cause the solution to become more red.

Answer 1

Decreasing the pH will release Fe3+ ions and cause the solution to become more red.

Reason: Lowering pH (adding H+) dissolves Fe(OH)3, increasing [Fe3+]. That increases the product concentration and shifts the equilibrium left, forming more FeSCN2+ (red).