Which one of the following is called an amphoteric solvent?

Hydrolysis of which of the following compounds liberates an acidic gas?

What is heavy water? Give its uses.

Which of the following is not true?

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

Explain: Proton $(H^{+})$ does not exist in aqueous solution.