pH + pOH =14 => pOH = 14-13 = 1
KOH = baza tare, ionizeaza complet in solutie apoasa => Cm = 10la-pH
=> Cm = 10la-1
Cm = n/Vs => n = CmxVs = 0,5x0,1 = 0,05 moli KOH
n = m/M , M(KOH) = 39+16+1 = 56 g/mol
=> m = nxM = 0,05x56 = 2,8 g KOH
