Question

which statement would indicate the presence of an acid?
○ it tastes bitter.
○ it does not react with active metals.
○ it reacts with active metals to form a gas.
○ it does not change the color of litmus paper

Explanation:

• Option A: Bitter taste is a property of bases, not acids (acids taste sour).
• Option B: Acids do react with active metals (e.g., Zn + H₂SO₄ → ZnSO₄ + H₂), so this is incorrect.
• Option C: Acids react with active metals (like Mg, Zn) to produce hydrogen gas (e.g., 2HCl + Mg → MgCl₂ + H₂), so this indicates an acid.
• Option D: Acids turn blue litmus paper red, so no color change means it is not an acid.

Answer:

C. It reacts with active metals to form a gas.