$A$ substance used as a moderator in nuclear reactors is

Which of the following salts contains interstitial water molecules?

What properties of water make it useful as a solvent? What types of compound can it $(i)$ dissolve,and $(ii)$ hydrolyse?

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

Which of the following statements is/are correct?

Identify the correct statements from the following.
$A$. In photosynthesis reaction,water is oxidized to oxygen.
$B$. An example for interstitial hydride is $MgH_2$.
$C$. Sodium hexametaphosphate is used in the removal of permanent hardness of water.