Which one has $sp^2$ hybridisation?

The ammonium ion $(NH_4^+)$ is:

In which of the following pairs,both the species have the same hybridisation?
$I$. $SF_4, XeF_4$
$II$. $I_3^-, XeF_2$
$III$. $ICl_4^+, SiCl_4$
$IV$. $ClO_3^-, PO_4^{3-}$

When $BCl_3$ is treated with water,it hydrolyses and forms $[B(OH)_4]^-$ only,whereas $AlCl_3$ in acidified aqueous solution forms $[Al(H_2O)_6]^{3+}$ ion. Explain what are the hybridizations of boron and aluminum in these species?

The hybridization in methane,ethene and ethyne respectively is

What is the hybridization state of the central atom in the conjugate base of $NH_4^{+}$ ion?