An acidic gas has no effect on dry blue litmus but turns moist blue litmus red. Why?
Answer and explanation
Correct answer: Ions form in the presence of water
Acidic behaviour is produced by ions in an aqueous medium, especially hydrogen or hydronium ions. A dry acidic gas cannot ionise sufficiently on dry litmus, so no colour change is observed. Moisture dissolves the gas and permits ion formation; these ions cause blue litmus to turn red. Hence option A is correct, while the other explanations are scientifically irrelevant or false.
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What is the correct answer to this question?
Ions form in the presence of water
Why is this the correct answer?
Acidic behaviour is produced by ions in an aqueous medium, especially hydrogen or hydronium ions. A dry acidic gas cannot ionise sufficiently on dry litmus, so no colour change is observed. Moisture dissolves the gas and permits ion formation; these ions cause blue litmus to turn red. Hence option A is correct, while the other explanations are scientifically irrelevant or false.
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.
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