Ph vrednost vodenog rastvora NaCH₃COO
Submitted by Roy Mustang on Mon, 06/16/2014 - 15:03
Forums:
Izracunati pH vrednost vodenog rastvora CH3COONa koncentracije 0.1 mol/dm^3.
Podatak: K(CH₃COO) = 1.8 · 10^(-5)
Hvala. :)
Izracunati pH vrednost vodenog rastvora CH3COONa koncentracije 0.1 mol/dm^3.
Podatak: K(CH₃COO) = 1.8 · 10^(-5)
Hvala. :)
CH3COONa----------------
CH3COONa---------------->CH3COO- + Na+
CH3COO- + H2O------------------->CH3COOH+OH-
Kb={CH3COOH}*{OH-}/{CH3COO-}
Kb=Kw/Ka=1*10(-14)/1.8*10(-5)=5.55*10(-10)
{CH3COOH}={OH-}=x
{CH3COO-}={CHCOONa}=0.1 mol/l
5.55*10(-10)=x2/0.1
x=(koren(5.55*10(-11)))=7.45*10(-6)
{OH-}=7.45*10(-6) mol/l
pOH= -log{OH-}=5.13 a pH=14-pOH=14-5.13=8.87