1.The brown ring test for NO2−\mathrm{NO_2^-}NO2− and NO3−\mathrm{NO_3^-}NO3− is due to formation of a complex ion with formula:a.[Fe(H2O)6]2+[\mathrm{Fe(H_2O)_6}]^{2+}[Fe(H2O)6]2+b.[Fe(CN)5(NO)]2−[\mathrm{Fe(CN)_5(NO)}]^{2-}[Fe(CN)5(NO)]2−c.[Fe(H2O)5(NO)]2+[\mathrm{Fe(H_2O)_5(NO)}]^{2+}[Fe(H2O)5(NO)]2+d.[Fe(H2O)(NO)5]2+[\mathrm{Fe(H_2O)(NO)_5}]^{2+}[Fe(H2O)(NO)5]2+Login to continueOnly logged in users canattempt or see the solution.