Complete and balance the following equation:

Mn²⁺ + PbO₂ $$\to$$ $$MnO_4^-$$ + H₂O

Complete and balance the following equation:

$$ClO_3^-$$ + I^- + H₂SO₄ $$\to$$ Cl^- + $$HSO_4^-$$

Arrange the following in increasing oxidation number of iodine.

I₂, HI, HIO₄, ICl

The electron density in the XY plane in 3d_{x² - y²} orbital is zero