The temporary hardness of water is due to

An inorganic salt $(A)$ is decomposed on heating to give two products $(B)$ and $(C)$. Compound $(C)$ is a liquid at room temperature and is neutral to litmus,while the compound $(B)$ is a colourless neutral gas. Compounds $(A)$,$(B)$ and $(C)$ are:

$100 \, mL$ 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 $146 \, g \, mol^{-1}$)

Deionized water is obtained by passing hard water through

Which of the following methods is the best test to detect the presence of water in a liquid?

Identify the reactions in which $H_2O$ is oxidised:
$I$. Photosynthesis
$II$. Reaction of $H_2O$ with fluorine
$III$. Reaction of $H_2O$ with hydrogen
$IV$. Reaction of $H_2O$ with $P_4O_{10}$
The correct answer is