Solution of which of the following oxides in
water will change the colour of blue litmus to red?
(a) sulphur dioxide (c) iron oxide
(b) magnesium oxide (d) copper oxide
Answers
Answer:
The non‑metal oxides dissolve in water to form acids. For example, (i) Carbon dioxide dissolves in water to form carbonic acid. A solution of carbon dioxide gas in water turns blue litmus to red showing it is acidic in nature.
Answer:
An acidic oxide is an oxide that releases acid when it reacts with water.
A basic oxide is an oxide that releases a base when it reacts with water.
Explanation:
The natural indicator is litmus paper.
Indicators in bases are blue while in acids they are red. In other words, bases turn red litmus paper blue whereas acids turn blue litmus paper red.
The acidic oxide is MgO. As a result, carbon dioxide, an acidic form of carbon, turns blue litmus red.
Oxides of potassium and magnesium are basic substances. So, they change the color of red litmus to blue.
Oxides of sulfur are acidic. So, they change the color of blue litmus to red.
Group I and II oxides are basic in nature. So they change the color to litmus blue. Examples are Na, K, Mg, and Ca.
Hence, the correct option is (a) sulfur dioxide.
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