Question

Which of the following anion (s) evolve(s) reddish brown gas with concentrated `H_(2)SO_(4)`?
A. `Br^(-)`
B. `NO_(3)^(-)`
C. `SO_(3)^(2-)`
D. `I^(-)`

Answer 1

Correct Answer - A,B
(A)`Br^(-)+H^(+)toHBruarr,2HBr+2H_(2)SO_(4)toBr_(2)uarr`(reddish brown)+`SO_(2)uarr+SO_(4)^(2-)+H_(2)O`
(B)`4NO_(3)^(-)+2H_(2)SO_(4)to4NO_(2)uarr`(reddish brown)`+O_(2) uarr+2SO_(4)^(2-)+2H_(2)O`
( C)`SO_(3)^(2-)+2H^(+)toSO_(2)uarr` (colourless)`+H_(2)O`
(D)`3I^(-)+2H_(2)SO_(4)toI_(3)^(-)uarr`(violet/purple)`+SO_(4)^(2-)+2H_(2)O+SO_(2)`