Hydrogen and oxygen are both gases. What compound is formed by their combination?

Which of the following is a good scientific method to detect the presence of water in a liquid?

Temporary hardness of water is due to the presence of

Which of the following salts contains interstitial water molecules?

Select the correct statement about water.
$(i)$ Critical temperature of $H_2O$ is less than $NH_3$.
$(ii)$ Standard boiling point of water is $100 \ ^oC$.
$(iii)$ Critical volume of $H_2O$ is less than $NH_3$.

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