Which compound is used to remove the temporary hardness of water in Clark's method?

Write chemical reactions to show the amphoteric nature of water.

The hydride ion $H^{-}$ is a stronger base than the hydroxide ion $OH^{-}$. Which of the following reactions will occur if sodium hydride $(NaH)$ is dissolved in water?

What is used to soften water by Clark's method?

Temporary hardness and permanent hardness can be removed by adding $........$ respectively.

$100 \, mL$ of a water sample contains $0.81 \, g$ of calcium bicarbonate and $0.73 \, g$ of magnesium bicarbonate. The hardness of this water sample expressed in terms of equivalents of $CaCO_3$ is .............. $ppm$ (molar mass of calcium bicarbonate is $162 \, g \, mol^{-1}$ and magnesium bicarbonate is $146 \, g \, mol^{-1}$)