Hey I'm a noob to physics however after reading about black holes and Hawking radiation. If a black hole made entirely out of negatively charged particles (say this black hole is made entirely of electrons) Then when it evaporates equal parts positive and negative particles (positrons and electrons for this example) are created. Doesn't this violate the law of conservation of charge?
There is an upper bound for the charge of a BH compared to its mass. It is given by $GM^2=Q^2$ in natural units. Where $G$ is newton's constant, $M$ the mass of the black hole and $Q$ the charge. If the charge exceeds this, it creates a naked singularity, which is forbidden by nature. This all can be found in Sean Carroll's notes on GR on pages 202-206.
Given this I think your thought experiment won't work since a BH made of only electrons will violate this but you can do the math yourself.
Hawking radiation comes from the horizon, not from the black hole itself, and the probability of + and - charge generated is equal as far as the model goes.
If you are worrying if your hypothetical black hole completely evaporates, i.e. no more horizon, it means that the electrons will just disperse due to the electrostatic repulsion, (once the body stops being a black hole).
As far as our observations and measurements go, conservation of charge is a strict law.