If the pH of a basic solution decreases from 13 to 10, what happens to its basicity?
Answer and explanation
Correct answer: Basicity decreases approximately one thousand times
The pH scale is logarithmic. A decrease from pH 13 to pH 10 is a change of three units, meaning the hydrogen-ion concentration increases by 10³, or 1,000 times. Equivalently, the hydroxide-ion concentration and the corresponding basic character decrease by about 1,000 times, assuming comparable conditions. The solution is still basic at pH 10, so option A is correct; it has not become acidic.
Frequently asked questions
What is the correct answer to this question?
Basicity decreases approximately one thousand times
Why is this the correct answer?
The pH scale is logarithmic. A decrease from pH 13 to pH 10 is a change of three units, meaning the hydrogen-ion concentration increases by 10³, or 1,000 times. Equivalently, the hydroxide-ion concentration and the corresponding basic character decrease by about 1,000 times, assuming comparable conditions. The solution is still basic at pH 10, so option A is correct; it has not become acidic.
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.
