Give reasons:(i) Sodium metal is kept in kerosene oil.(ii) Platinum, g

1.	Give reasons:(i) Sodium metal is kept in kerosene oil.(ii) Platinum, gold and silver are used to make jewellery.(iii) Tarnished copper vessels are cleaned.
Answer» (i) Na, K, Li etc. are very reactive so these metals react vigorously with atmospheric oxygen to form oxides. Storing them in oil prevents their oxidation. (ii) Platinum, gold and silver are least reactive, so they are not corroded by air and water easily. (iii) Copper vessels get tarnished by reacting with air and water, due to which a layer is formed mainly contains black copper oxide and green copper hydroxide which is basic in nature. The citric acid in lemon dissolves this layer and washes off easily.

Give reasons:(i) Sodium metal is kept in kerosene oil.(ii) Platinum, gold and silver are used to make jewellery.(iii) Tarnished copper vessels are cleaned.

Answer»

(i) Na, K, Li etc. are very reactive so these metals react vigorously with atmospheric oxygen to form oxides. Storing them in oil prevents their oxidation.

(ii) Platinum, gold and silver are least reactive, so they are not corroded by air and water easily.

(iii) Copper vessels get tarnished by reacting with air and water, due to which a layer is formed mainly contains black copper oxide and green copper hydroxide which is basic in nature. The citric acid in lemon dissolves this layer and washes off easily.

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