Subject: Inorganic Chemistry · Chapter: Coordination Chemistry · Topic: Coordination Chemistry – General · Exam: NET DEC 2015 · Marks: 2 · Difficulty: Medium
Identify the complex ions in sequential order when ferroin is used as an indicator in the titration of iron(II) with potassium dichromate, (phen = 1, 10-phenathroline)
(a)$\left[\mathrm{Fe}(\text { phen })_{3}\right]^{2+}$ and $\left[\mathrm{Fe}(\text { phen })_{3}\right]^{3+}$
(b)$\left[\mathrm{Fe}(\mathrm{phen})_{3}\right]^{3+}$ and $\left[\mathrm{Fe}(\mathrm{phen})_{3}\right]^{2+}$
(c)$\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{4-}$ and $\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-}$
(d)$\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-}$ and $\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{4-}$