Basic water chemistry: Water having pH = 6 at ambient conditions is classified as

Introduction / Context:
The pH scale quantifies acidity/alkalinity of water on a logarithmic basis. Understanding pH classifications is essential for corrosion control, coagulation, disinfection efficacy, and consumer acceptability in water-supply engineering.

Given Data / Assumptions:

• Neutral pH at 25°C is approximately 7.0.
• Values below 7 are acidic; values above 7 are alkaline (basic).
• Measured pH is 6.

Concept / Approach:
Classify pH numerically relative to neutrality. Consider implications for pipe materials and treatment chemistry (e.g., alkalinity adjustment, corrosion indices).

Step-by-Step Solution:

Verification / Alternative check:
Logarithmic nature: each pH unit represents a tenfold change in hydrogen-ion activity, so pH 6 is ten times more acidic than pH 7 (in terms of [H+]).

Why Other Options Are Wrong:
Alkaline and neutral categories contradict the numeric definition; “none of these” is unnecessary because “acidic” is exact.

Common Pitfalls:
Ignoring temperature effects on neutral pH (slight shift from 7.0), which does not change classification here.

Final Answer:
acidic