HgCl2 and I2 both when dissolved in water containing I- ions, the pair of species formed is
- HgI2, I-
- HgI42-, I3-
- Hg2I2, I-
- HgI2, I3-
Answer
(2) HgI42-, I3-
Solution
HgCl2 with I- first gives HgI2, which dissolves in excess I- forming the complex ion HgI42-:
HgCl2 + 2I- HgI2 + 2Cl-
HgI2 + 2I- HgI42-
Iodine dissolves in water containing I- by forming the triiodide ion:
I2 + I- I3-
∴ The pair of species formed is HgI42- and I3-.
Answer: (2)