5 ml of this aliquot was taken and 0.3 ml of NaNO2 (5%) was added, kept for 5 min followed by addition of 0.3 ml of AlCl3 (10%), againkept for 6 min followed by addition of 2 ml sodium hydroxide (1 N) solution.
5 ml of thisaliquot was taken and 0.3 ml of NaNO2 (5%) was added, keptfor 5 min followed by addition of 0.3 ml of AlCl3 (10%), againkept for 6 min followed by addition of 2 ml sodium hydroxide(1 N) solution.