Question

What conjugate base(s) will deprotonate water$?$

Answer 1

First we have to know what deprotonation is. Then we know what is a base and conjugate base. Then mention the conjugate bases will deprotonate water.

Complete answer:
Deprotonation means removing the most acidic proton of the compound by a base that you need to choose. We call it a base because if the given compound is deprotonated then it is a proton donor and by Brønsted–Lowry definition the proton donor is the acid in an acid-base reaction.
The conjugate base of any acid with a $pKa$ greater than water will deprotonate water. Hence the conjugate bases of functional groups alkane (example is $C{H_4}$), Amine (example is $:N{H_3}$) and alkyne(example is methane).
A conjugate acid of that base that can either accept or donate a proton is referred to as amphiprotic. Hence, the $H_2O$ (water) molecule, which can gain a proton to form the hydronium ion (${H_3}{O^ + }$), or lose a proton, leaving the hydroxide ion ($O{H^ - }$).
The relative ability of a molecule to give up a proton is measured by its $pKa$ value. A low $pKa$ value indicates that the compound is acidic and will easily give up its proton to a base. The $pKa$ of a compound is determined by many aspects, but the most significant is the stability of the conjugate base. This is determined by the ability of the conjugate base to stabilize negative charge. One of the most important ways of assessing a conjugate base's ability to distribute negative charge is using resonance. (which can stabilize the molecule by increasing charge distribution) or electron donating groups (which destabilize by decreasing charge distribution) present on a molecule also determine its $pKa$. The solvent used can also assist in the stabilization of the negative charge on a conjugate base.

Note:
Note that Deprotonation is also known as Dehydronation. The $pKa$ value is used to indicate the strength of an acid. $pKa$ is the negative log of the acid dissociation constant or $Ka$ value. A lower $pKa$ value indicates a stronger acid. That is, the lower value indicates the acid more fully dissociates in water.