CH3NH3 is the conjugate acid of methylamine (CH3NH2), a weak base.

Here's why:

* Methylamine (CH3NH2) is a weak base. It accepts a proton (H+) to form its conjugate acid, CH3NH3+.

* Conjugate acids of weak bases are weak acids. This means that CH3NH3+ will only partially donate a proton in solution.

Therefore, CH3NH3 is a weak acid, not a strong acid.