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?

Permanent hardness in water cannot be cured by

Which of the following reagents is not used for the removal of permanent hardness of water?

Identify the statements which are not correct from the following:
a) In the structure of ice,each oxygen atom is surrounded by $4$ other hydrogen atoms via hydrogen bonding.
b) Temporary hardness of water is due to dissolved $Mg(HCO_3)_2$ and $Ca(HCO_3)_2$,not $NaHCO_3$.
c) In the reaction of acidified $KMnO_4$ and $H_2O_2$,$H_2O_2$ acts as a reducing agent.
d) $3 \ g \ L^{-1}$ $H_2O_2$ is not equal to $100$ volume $H_2O_2$ (since $100$ volume $H_2O_2$ is approximately $303.7 \ g \ L^{-1}$).

The decreasing order of hydrogen bonding in the following forms of water is correctly represented by:
$A.$ Liquid water
$B.$ Ice
$C.$ Impure water

When zeolite (hydrated sodium aluminium silicate) is treated with hard water,the sodium ions are exchanged with: