Identify the correct statement from the following.

Assertion : Sulphuric acid is more viscous than water.
Reason : Concentrated sulphuric acid has a great affinity for water.

The maximum sum of the number of neutrons and protons in an isotope of hydrogen is

Identify the correct statements from the following:
$i$. Reaction of hydrogen with fluorine occurs even in dark.
$ii$. Manufacture of ammonia by Haber process is an endothermic reaction.
$iii$. $HF$ is an electron-rich hydride.

Identify the reactions in which $H_2$ is liberated? $(i)$ $Zn + NaOH_{(aq)} \longrightarrow$ $(ii)$ $HCOOH \xrightarrow[\text{Conc. } H_2SO_4]{373 \ K}$ $(iii)$ $CH_{4(g)} + H_2O_{(g)} \xrightarrow[Ni]{1270 \ K}$ $(iv)$ $Zn + H^+_{(aq)} \longrightarrow$ $(v)$ $C_{(s)} + H_2O_{(g)} \xrightarrow{1270 \ K}$

Among the following,the correct statements are:
$I$. $LiH, BeH_2$ and $MgH_2$ are saline hydrides with significant covalent character.
$II$. Saline hydrides are volatile.
$III$. Electron-precise hydrides are Lewis bases.
$IV$. The formula for chromium hydride is $CrH$.
The correct option is: