What is the difference between a strong acid and a weak acid in terms of pH ranges?

• A. A strong acid lies between pH 0 and 2, a weak acid between 3 and 6; 7 is neutral.
• B. A weak acid has pH above 7.
• C. A strong acid has pH above 7.
• D. There is no difference.

Answer: (A)

The key idea is how the strength of an acid affects the amount of hydrogen ions in solution, which sets the pH. Strong acids dissociate completely in water, releasing a lot of H+ and giving very low pH values. Weak acids only partially dissociate, so they produce fewer H+ ions and have higher pH values for the same concentration. Because of that, a typical strong acid solution sits in the very acidic range (about pH 0–2), while a typical weak acid solution sits higher in the acidic range (about pH 3–6). The neutral point is pH 7.

So the statement that matches this general pattern—strong acids around pH 0–2 and weak acids around pH 3–6, with 7 being neutral—is the best description. Remember, the exact pH depends on concentration, but the trend remains: strong acids are much more acidic (lower pH) than weak acids.