Question

Bhavna took a pale green substance a in a test tube and heated it over the flame of a burner a brown colour Residue be was formed along with Evolution Of two gases with burning smell of sulphur identify A and B write the chemical reaction involved

Answer 1

The green colour substance is Ferrous sulphate.
When ferrous sulphate is heated strongly, it decomposes to form ferric oxide, sulphur dioxide and sulphur trioxide : 
    2FeSO4(s)        −→heat Fe2O3(s)         +SO2(g)            + SO3(g)Ferrous sulphate       Ferric Oxide       Sulphur              Sulphur(Green Colour)         (Brown Colour)     dioxide              trioxide

This is a decomposition reaction since one substance is splitting up into three substances.  In this reaction , the green colour of ferrous sulphate changes to brown due to the formation of ferric oxide . A smell of burning sulphur is obtained due to the the formation of sulphur dioxide.
Hope it helps.....pls mark brainliest........

Answer 2

HI there !!

Ferrous sulphate(FeSO₄) is green in colour.

When heated , it decomposes to form ferric oxide (Fe₂O₃) , which is reddish brown in colour , and two gases , namely , Sulphur dioxide (SO₂) and Sulphur trioxide (SO₃) are evolved.
 
                 heat
2FeSO₄ ------------> Fe₂O₃ + SO₂ + SO₃ .

This reaction is and example of decompostion reaction .
As this reaction needs heat to take place , this reaction is categorized as thermal decomposition reaction.

The burning smell of sulphur is obtained as sulphur dioxide gase and trioxide gas evolved.

Hope this Helps You !!