Which of the following statements are INCORRECT regarding Brown ring test for detection of $N{O}_3^{-}$  ion?

To an aqueous solution of salt, Conc. $H_{2}S{O}_4$ and freshly prepared $FeS{O}_4$ are added and thoroughly mixed by shaking and heating the test tube

To an aqueous solution of salt, Conc. $H_{2}S{O}_4$ is added slowly, mixed thoroughly, cooled and then freshly prepared $FeS{O}_4$ solution is added along the sides of test tube, drop wise

To an aqueous solution of salt, first freshly prepared  $FeS{O}_4$ solution is added and  then conc. $H_{2}S{O}_4$  is added along the sides of test tube, drop wise

$AgN{O}_3$  does not give Brown ring test