calculate ph of the solution at 25 degrees that is formed by the dilution of a 20ml solution of 0.1m naoh to 50ml

Answer 1

I assume you mean 0.1 M (and not m). M stands for molarity. m stands for molality.
(NaOH) = (OH^-) = 0.1 M x (20 mL/50 mL) = 0.04 M
So pOH = -log(0.04). For pH, use
pH + pOH = pKw = 14. You know pOH and pKw, solve for pH.
Post your work if you get stuck.