Question

Which among the following methods can give soluble complexes of Ca and Mg in water
1) Clark's process
2) Permutit process
3) Calgon process
4) Use of organic ion exchange resins​

Answer 1

Answer:

Clark's method is correct option

Explanation:

In Clark's process, slaked lime,Ca(OH)2 is added to temporary hard water. Insoluble calcium carbonate precipitate out and no longer produce hardness.

Clark's process involves the addition of a controlled quantity of slaked lime (calcium hydroxide)

Ca(HCO3)2 (aq)+Ca(OH)2(aq)→2CaCO3(s)+2H2O(l)

Mg(HCO3)2(aq)+Ca(OH)2(aq)→CaCO3(s)+MgCO3

(s)+2H2O(l)

Slaked lime is itself a source of calcium ions (and hence hardness) so care must be taken to avoid adding an excess.

Answer 2

The methods can give soluble complexes of Ca and Mg in water 1) Clark's process.

• In the Clarks method, water is softened by using slaked lime or Ca(OH)2.
• As slaked lime is used in this process so it is known as Clark's reagent.
• In this process reaction between insoluble salts of magnesium becomes soluble to Mg(OH)2 and CaCO3 precipitated.
• Permutit method is used for softening hard water by using zeolite and in the ion exchange method resins are exchanged and water is softened.