Question

which substance acts as a buffer in natural water?
a. distilled water
b. minerals and salts
c. sulfuric acid
d. a ph indicator

Explanation:

A buffer resists pH change. Distilled water (A) has no buffering components. Sulfuric acid (C) is a strong acid, not a buffer. A pH indicator (D) only shows pH, not buffer. Minerals and salts (B) in natural water (like carbonates, bicarbonates from minerals) form buffer systems to stabilize pH.

Answer:

B. Minerals and salts