Question

When the powder of a common metal is heated in an open china dish its color turns black. Substance so

formed. It regains its original color based on the above information answer following questions:-

a) What type of chemical reaction takes place in each of the two given steps?

b) Name the metal initially taken in the powder form. Write balanced chemical equations for both

reactions.
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Answer 1

Answer:

(1) In first step, oxidation reaction occurs and in second step, reduction reaction occurs.

(2) The name of metal is, copper (Cu) and the balanced chemical reaction will be,

Oxidation :

Reduction :

Explanation :

Step 1 : When the powder of a cooper metal is heated in an open china dish its color changes to black.

The balanced chemical reaction is,

This is a oxidation reaction where oxygen is gained by the copper metal.

step 2 : When hydrogen is passed over the hot black substance that is , it regains its original color and form copper as a metal.

The balanced chemical reaction is,

It is a reduction reaction where hydrogen is gained by the cooper oxide.

(If u dontdon't understand iI will tell in another way)

metal initially taken is Cu

2Cu+O2---->2CuO (black)

when hydrogen is passed over CuO it regains its original color

CuO+H2 ----->Cu+H2O

Sorry my grammar isn't that good

Explanation: