Question

Determinati pH si pOH-ul unei solutii obtinute prin reactia a 1,3g K cu 300 g H20 ro final =1.02g/mL.

Answer 1

K + H2O ⇒ KOH + 1/2H2
nK = 1,3/39 = 1/30 moli = nKOH = nH2O reactionat (mH2O react,= 0,6g)
solutia finala   ms = mKOH + mH2O ramas = 1/30 ·56 +299,4 = 301,266 g
Vs = ms·q = 307,292 ml = ≈0,3 l
[KOH] =( 1/30)/0,3 = 0,1 mol/l = [HO⁻]       pOH = - lg0,1 = 1
pH = 14 - pOH =13