Question

a compound A is green in colour on heating it gives a gas B which turns limewater milky. the residue left C is black in colour identify A B and C write the chemical reaction involved.

Answer 1

A is copper carbonate
B is carbon dioxide
C is copper oxide

Answer 2

Answer: Compound A is copper carbonate, B is carbon dioxide and C is copper oxide.

Explanation:

The gas which is released after heating compound A, turns lime water milky which means that the gas is carbon dioxide and compound A must have a carbonate compound in it.

The carbonate compound which is green in color is copper carbonate and on heating, it decomposes into carbon dioxide and copper oxide which is black in color.

The equation for the decomposition of copper carbonate follows:

$CuCO_3(s)\overset{\Delta}\rightarrow CuO(s)+CO_2(g)$

Hence, compound A is copper carbonate, B is carbon dioxide and C is copper oxide.