Question

Universal indicator is

• A. The indicator that changes its color at different iodide ion concentration
• B. The indicator that shows different colors at different hydrogen ion concentrations
• C. Is effective only at low hydrogen ion concentration
• D. Gives the same color at different $pH$

Answer 1

The correct option is B

The indicator that shows different colors at different hydrogen ion concentrations

Explanation of correct option:

The correct option is B:

1. The universal indicator can be defined as the $pH$ indicator that changes the color for different hydrogen ion concentrations.
2. The hydrogen ion concentration determines the nature of the solution i.e acidity or basicity. And the universal indicator shows the different colors for the different $pH$ values according to the acidity or basicity of the solution.

Explanation of incorrect option:

Option A:

• The universal indicator changes its color for different $pH$ values, not according to iodide ion concentration.

Option B:

• The universal indicator shows the color change for both low and high hydrogen ion concentrations.

Option D:

• It produces different colors for different $pH$ values.

Final Answer: Universal indicator is the indicator that shows different colors at different hydrogen ion concentrations