${\text{FeSO}}_{\text{4}}$  is used in brown ring test for nitrates. In this test, a freshly prepared ${\text{FeSO}}_{\text{4}}$  solution is mixed with solution containing $N{O}_3^{-}$  and the conc.  ${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}$ is run down the side of test tube. If the mixture gets hot or shaken and left in air:
(I) Brown ring disappears 

(II) $N{O}_{\left(g\right)}$ is evolved
(III) a yellow solution or precipitate of ${\text{Fe}}_{\text{2}}{\left({\text{SO}}_{\text{4}}\right)}_{\text{3}}$can be formed
Identify the correct statements: