Question

13.
(a) An element X on reacting with oxygen forms an oxide X20. The oxide
dissolves in water and turns blue litmus red. Predict the element is metal or
non-metal.
(b) A solution of copper sulphate was kept in an iron pot. After few days, the pot
developed some holes in it. How will you account for this?
3​

Answer 1

(a) Litmus paper acts as an acid base indicator.

An Acidic solution turns – blue litmus paper to red

A basic solution turns – Red litmus paper to blue

According to the question, the given oxide X2O turns blue litmus red. This implies the solution is acidic in nature.

Now, we know that non metal oxides are acidic in nature. For example, CO₂ is oxide of Carbon and it is a non-metallic gas. When CO₂ reacts with water, carbonic acid is formed, from which hydrogen ions dissociate.

CO₂ + H₂O → H₂CO₃

Whereas, most of the oxides of metals are basic.

For example, when sodium oxide is dissolved in water, it produces sodium hydroxide, which is a strong base.

Na₂O + H₂O → 2NaOH

Hence, we can say X is a non-metal.

(b) Fe is more reactive than Cu and hence, it displaces the less reactive Cu from CuSO₄ solution. In this case, iron metal from iron pot is participating in the reaction due to which holes are formed in the vessel. The reaction involved here is,

CuSO₄(aq) + Fe (s) = FeSO₄ +Cu

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Answer 2

Answer:

Explanation:

(a) Litmus paper acts as an acid base indicator.

An Acidic solution turns – blue litmus paper to red

A basic solution turns – Red litmus paper to blue

According to the question, the given oxide X2O turns blue litmus red. This implies the solution is acidic in nature.

Now, we know that non metal oxides are acidic in nature. For example, CO₂ is oxide of Carbon and it is a non-metallic gas. When CO₂ reacts with water, carbonic acid is formed, from which hydrogen ions dissociate.

CO₂ + H₂O → H₂CO₃

Whereas, most of the oxides of metals are basic.

For example, when sodium oxide is dissolved in water, it produces sodium hydroxide, which is a strong base.

Na₂O + H₂O → 2NaOH

Hence, we can say X is a non-metal.

(b) Fe is more reactive than Cu and hence, it displaces the less reactive Cu from CuSO₄ solution. In this case, iron metal from iron pot is participating in the reaction due to which holes are formed in the vessel. The reaction involved here is,

CuSO₄(aq) + Fe (s) = FeSO₄ +Cu