pH

milicandj's picture

U 1 dm3 vodenog rastvora nalazi se 30 grama ciste sircetne kiseline (KA= 1,8 x 10-5 mol/dm3 ). Koncentracija Hjona u rastvoru je?

milicaradenkovic's picture

CH3COOH-------------->CH3COO- + H+

n(CH3COOH)=m/Mr=30/60=0.5 mol

c(CH3COOH)=n(CH3VOOH)/V=0.5/1=0.5 mol/l

{CH3COO-}={H+}=x

Ka={CH3COO-}*{H+}/{CH3COOH}

1.8*10(-5)=x2/0.5

x=(koren(9*10(-6)))=3*10(-3)

{H+]=3*10(-3) mol/l

pH= -log{H+}=2.52