Why does HCl dissociate in water but not in methylbenzene?

Water is a polar solvent and methylbenzene is a non-polar solvent. A polar solvent will have positive and negative charge (in water, oxygen is slightly more negative and the hydrogen is slightly positive) whereas methylbenzene is netral throughout. HCl will dissociate in water because HCl is also a polar molecule (Cl is slightly negative and H is slightly positive). The Cl will be attracted to the slightly positive H in water and the H will be attracted to the slightly negative O in water. The HCl molecule will dissociate as a result because of these strong attractions. With methylbenzene, no such attraction exists, thus HCl will not dissociate.