An acidic gas has no effect on dry blue litmus but turns moist blue litmus red. What is the correct reason?
Answer and explanation
Correct answer: Ions form in the presence of water
An acid shows its characteristic behavior in aqueous medium, where it ionizes and produces hydronium ions, H3O+. Dry blue litmus contains insufficient water for the acidic gas to ionize effectively, so no colour change is observed. Moist litmus provides water; the gas dissolves, forms hydronium ions, and changes blue litmus to red. Therefore option A is correct, while the other statements confuse the role of moisture.
Frequently asked questions
What is the correct answer to this question?
Ions form in the presence of water
Why is this the correct answer?
An acid shows its characteristic behavior in aqueous medium, where it ionizes and produces hydronium ions, H3O+. Dry blue litmus contains insufficient water for the acidic gas to ionize effectively, so no colour change is observed. Moist litmus provides water; the gas dissolves, forms hydronium ions, and changes blue litmus to red. Therefore option A is correct, while the other statements confuse the role of moisture.
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.
