Which statement describes the behavior of acids like HNO3 and CH3COOH with litmus paper?

Which statement describes the behavior of acids like HNO3 and CH3COOH with litmus paper?

• A. They turn blue litmus red.
• B. They turn red litmus blue.
• C. They do not affect litmus.
• D. They turn litmus green.

Answer: (A)

Acids turn blue litmus paper red because they create an acidic environment with a low pH. When substances like HNO3 or CH3COOH dissolve in water, they donate H+ ions, which shifts the litmus dye from its blue form to red. Even though CH3COOH is a weaker acid than HNO3, both still produce enough H+ to change blue litmus to red. The other options describe either basic conditions (which turn red litmus blue), neutrality (no color change), or an unlikely litmus color (green), none of which match how acids behave.

Acids turn blue litmus paper red because they create an acidic environment with a low pH. When substances like HNO3 or CH3COOH dissolve in water, they donate H+ ions, which shifts the litmus dye from its blue form to red. Even though CH3COOH is a weaker acid than HNO3, both still produce enough H+ to change blue litmus to red. The other options describe either basic conditions (which turn red litmus blue), neutrality (no color change), or an unlikely litmus color (green), none of which match how acids behave.