Frequency and pitch are the same thing, though pitch applies only to sound, and usually is applied only to audible sound.
Tone, I think can be context-dependent -- could mean pitch or timbre, the latter being a more complex characteristic involving a set of frequencies interfering (constructively and destructively) with each other. This latter quality is BSM (Beyond the Scope of the MCAT).
If you want more details, give a specific problem using the word "tone" to describe sound.