Scenario: You are testing two different household solutions with your cabbage indicator, using the color key to the right.One solution turns blue. A possible hydrogen ion concentration for this solution is:

A blue cabbage-indicator color suggests the solution is basic. Basic solutions have a hydrogen ion concentration below 1 × 10⁻⁷ M; among the choices, 1 × 10⁻⁸ M fits. The larger concentrations listed would indicate acidic solutions.

AI-written and checked against the verified answer.