Viscosity adverse pressure gradient

[Captfahad]

I was reading about adverse pressure gradient cause seperation of airflow on wiki i know airflow travels from high pressure to low pressure then high pressure after air passes over the thickest point it starts to deaccelerate and the air which is near the surface slows down due to friction and the boundary layer starts to thickens sooo the stopping of air near the surface makes high adverse pressure gradient? ...

And what about viscosity flow does viscosity increases with airspeed over wing or it becomes inviscid?

And is renold numbers of airfoils is less then 2300?

Am sorry if my questions are lame but i need to know this they are sooo confusing...