What is $X$ in the following reaction?
$MgCl_2 + 2H_2O \to X + 2HCl + H_2O$

What is Calgon,used for softening water?

Which of the following methods is used for the removal of temporary hardness of water?

When the first element of the periodic table is treated with dioxygen,it gives a compound whose solid state floats on its liquid state. This compound has an ability to act as an acid as well as a base. What products will be formed when this compound undergoes autoionisation?

$A$ sample of water contains $Mg(HCO_3)_2$ and $Ca(HCO_3)_2$. On boiling this water, these hydrogen carbonates are removed as precipitates. The precipitates are

$D_2O$ is used more in