Fe^(+3) ions in an aqueous solution gives deep red colouration with both sodium acetate (in excess) and ammonium thiocyanate(slightly acidic). The deep red colouration obtained with ammonium thiocyanate gets decolourised on addition of a solution containing F^(-) ions. Excess of sodium acetate is added in the reaction with Fe^(3+) ions because:

Fe^(+3) ions in an aqueous solution gives deep red colouration with bo

1.	Fe^(+3) ions in an aqueous solution gives deep red colouration with both sodium acetate (in excess) and ammonium thiocyanate(slightly acidic). The deep red colouration obtained with ammonium thiocyanate gets decolourised on addition of a solution containing F^(-) ions. Excess of sodium acetate is added in the reaction with Fe^(3+) ions because:
Answer» it ACTS as a buffer to CONTROL pH of the reaction other wise reaction is made reversible it makes the solution STRONG alkaline which destroys acidic effect if any it makes the solution acidic which destroys alkaline effect if any None of the above Solution :`Fe(SCN)_(3) OVERSET(F^(-))rarr [feF_(6)]^(3-)` colourless `(sp^(3)d^(2))` `underset(("Red colouration"))([Fe_(3)(OH)_(2)(CH_(3)COO)_(6)]^(+))+4H_(2)O rarr underset(("Red ppt"))(3Fe(OH)_(2)CH_(3)COOdarr)+3CH_(3)COOH +H^(+)`