Answer:

To determine which of the given molecules/ions have all the bonds not equal, we need to consider their Lewis structures and identify any instances where the bonding pairs are not evenly distributed.

1) XeF4:
In the Lewis structure of XeF4, the central xenon (Xe) atom is surrounded by four fluorine (F) atoms. Each fluorine atom forms a single bond with the xenon atom. Since all the bonding pairs in XeF4 are evenly distributed, the bonds are equal.

2) F4–:
In the Lewis structure of F4–, there are four fluorine (F) atoms surrounding a negatively charged fluorine ion (F–). Each fluorine atom forms a single bond with the central fluorine ion. Since all the bonding pairs in F4– are evenly distributed, the bonds are equal.

3) SiF4:
In the Lewis structure of SiF4, the central silicon (Si) atom is surrounded by four fluorine (F) atoms. Each fluorine atom forms a single bond with the silicon atom. Since all the bonding pairs in SiF4 are evenly distributed, the bonds are equal.

4) SF4:
In the Lewis structure of SF4, the central sulfur (S) atom is surrounded by four fluorine (F) atoms. However, in SF4, the distribution of bonding pairs is not symmetrical. This is due to the presence of a lone pair of electrons on the sulfur atom, which affects the bonding geometry. The lone pair creates an electron-electron repulsion, causing the bonding pairs to be slightly displaced. Therefore, the bonds in SF4 are not equal.

Hence, in the given molecules/ions, only SF4 has bonds that are not equal.

How it can be Done it should be c option