The pH of an acidic solution changes from 1 to 4. What happens to acidity?
Answer and explanation
Correct answer: It decreases one thousand times
The governing concept is the logarithmic pH scale: pH = −log[H⁺]. A rise of one pH unit means a tenfold decrease in hydrogen-ion concentration. The change from pH 1 to pH 4 is three units, so acidity changes by 10 × 10 × 10 = 1000 times downward. Thus option A is correct; B treats pH as a linear scale, while C and D give the wrong direction or ignore the change.
Frequently asked questions
What is the correct answer to this question?
It decreases one thousand times
Why is this the correct answer?
The governing concept is the logarithmic pH scale: pH = −log[H⁺]. A rise of one pH unit means a tenfold decrease in hydrogen-ion concentration. The change from pH 1 to pH 4 is three units, so acidity changes by 10 × 10 × 10 = 1000 times downward. Thus option A is correct; B treats pH as a linear scale, while C and D give the wrong direction or ignore the change.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Acids, Bases, and Salts.
