Question

cao+co2 gives caco3 substance oxidized and agent​

Answer 1

Answer:

Explanation:

To see whether the given reaction is redox reaction or not, we have to look at the change in oxidation number of all elements taking part in reaction i.e. reactant and product both

If the oxidation number of an element increase, then it is oxidation and if it is decreased then it is reduction.

But in the above reaction, the oxidation number of 

Ca remains as +2

C remains as +4

and O remains as -2

So, there is no change in oxidation number, so it's not redox reaction.

Actually it is thermal decomposition reaction.

And yes, same element can be oxidized and redused ,both, but it can only be seen through their change in oxidation number

To know the oxidation number,

CaCO₃ - valency of Ca is 2, and this is a metal, so +2

C, valency is 4, it's oxidation number is +4 as it is bonded with O and valency of O is 2 having oxidation number -2 as it is  non- metal.

See for example, to find the oxidation number of CO₂

⁻²O=C²⁺²=O⁻²