Question

$\bullet \: \: \sf Chapter:Acids, \: bases \: and \: salts.$


Give suitable reasons for the following:

=> Rainwater conducts electricity but distilled water does not.
=> The crystals of washing soda change to white powder on exposure to air.
=> A tarnished copper vessel regains it's shine when rubbed with lemon.

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Answer 1

$\huge\mathtt{Hello!}$

1. Distilled water is pure and it cannot conduct electricity because it doesn't form ions

2. The crystals of washing soda change to white powder on exposure to air because they lose water of crystallization

3. Because when copper oxide is formed on the copper vessel, lemon can dissolve the layer of copper oxide since it's an acid.

[Btw water of crystallization is a fixed number of water molecules in one unit of salt]

Have a nice evening!

Answer 2

$\huge\sf \: 1.$

Question:-

• Give reason why rainwater conducts electricity but distilled water does not.

Answer:-

• Here , in rain water it contains electricity whereas distilled water doesn't . Rain water consists dissolved $\sf \: SO_2 , Co_2$.

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Question:-

• Why the crystals of washing soda change to white powder on exposure to air.

Answer:-

• Crystals of washing soda turn into white powder when exposed to air because it loses its molecule of water.

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Question:-

• Why a tarnished copper vessel regains it's shine when rubbed with lemon.

Answer:-

• Tarnished copper vessel regains it's shine when rubbed with lemon because the oxide layer is formed on the surface of copper and it is basic in nature.