Answer
Iodide ion ($I^-$) is the conjugate partner of $HI$.
Work Step by Step
1. Identify if the substance is an acid or a base (or both):
- HI is an acid.
2. Since $HI$ is an acid, remove one proton from it:
- Remove one hydrogen and subtract one from the charge:
$HI -- \gt I^-$
- This is the conjugate base of $HI$.
3. Name it:
Ions of nonmetals from group $VII$ receive an "ide" to the name of the element stem name:
$I$ = "Iod"
Ion: Iodide.
