Question

Write word and chemical equation for the chemical change taking place in magnesium salt during the softening of hard wate

Answer 1

Answer:

The water is treated with a combination of slaked lime, Ca(OH)2, and soda ash, Na2CO3. Calcium precipitates as CaCO3, and magnesium precipitates as Mg(OH)2. These solids can be collected, thus removing the scale-forming cations from the water supply.

Answer 2

During softening of hard water the Magnesium ions react  with slaked lime and sodium carbonate and gets precipitated.The reaction is given :

Mg²⁺ +2 OH⁻ --> Mg(OH )₂

Explanation:

Water

It is of two types :

Hard water

soft water

Hard water : It is that which contains calcium and magnesium salts .

Soft water : It is that which do not contain such ions .

Hardness of water : It has to be removed to make it useful for many purposes .

1. Hard water is water that contains cations with a charge of +2, especially Ca²+ and Mg²+.
2. Normally, the OH⁻ ions react with Magnesium ions and calcium ions to form insoluble precipitate  called scum that sticks to cloth .
3. During softening of hard water ,the water is treated with a combination of slaked lime, Ca(OH)₂, and soda ash, Na₂CO₃.
4. The Calcium precipitates as CaCO₃, and magnesium precipitates as Mg(OH)₂.
5. These solids can be collected and removed .
6. Thus water is softened .