Question

mention any 2 method of reneval of hardness of water

Answer 1

1) Chemical Water Softeners is one way of removal of hardness of water. These lead to precipitation. They  remove dissolved calcium, magnesium or iron or  salt by forming precipitate or undissolved solids. The precipitate is then removed by filtration.

2)You can also heat the water. The CaCO3 formed will precipitate out and the water will be less hard, maybe soft enough.

Hope it helps!