Q1. Write two reactions for each of the following
characteristic:
(Change of colour
(ii) Change of state
Pls help me sir
Answers
1.Evolution of gas:
The chemical reaction between zinc and dilute sulphuric acid is characterized by the evolution of hydrogen gas.
Zn(s)+H2SO4(aq)→ZnSO4(aq)+H2(g)
2.Change in colour:
The reaction between the lead nitrate solution and potassium iodide solution.
Pb(NO3)2(aq)+2KI→PbI2(s)+2KNO3(aq)
In this reaction colour changes from colourless to yellow.
3.Formation of precipitate:
The action of Barium Chloride on sodium sulphate.
BaCl2(aq)+Na2SO4(aq)→BaSO4(s)+2KNaCl(aq)
4.Change in temperature:
The action of dilute sulphuric acid on zinc:
Zn(s)+H2SO4(aq)→ZnSO4(s)+H2(g)
In this reaction, heat is evolved.
5.Change in the state:
When the wax is burnt in the form of the wax candle then water and carbon dioxide are formed. Wax is solid, water is a liquid whereas carbon dioxide is a gas.