Masa NaClO

Submitted by Serdjo on Sun, 02/09/2014 - 16:48
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Nepoznata masa NaClO je rastvorena u vodi, tako da je ukupna zapremina rastvora 2,00dm^3. pH rastvora je 10,5. Koliko je g ove soli rastvoreno u vodi? Kb= 3,3 * 10^-7 moldm^-3

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milicaradenkovic - Sun, 02/09/2014 - 20:57

NaClO+H2O--------------->HClO+NaOH

HClO+H2O--------------->ClO- + H3O+

ClO-+H2O----------------->HClO+OH-

{H+}=3.16*10(-11) mol/l

Kb={HClO}*{OH-}/{ClO-}

{OH-}=Kw/{H3O+}=1*10(-14)/3.16*10(-11)=3.16*10(-4) mol/l

{HClO}={OH-}=3.16*10(-4) mol/l

3.3*10(-7)=(3.16*10(-4))*2/{ClO-}

{ClO-}=0.302 mol/l

NaClO------------------->Na+ + ClO-

{NaClO}={ClO-}=0.302 mol/l

n(NaClO)={NaClO)/Vu=0.302/2=0.151 mol

m(NaClO)=n(NaClO)*Mr=0.151*74.5=11.25 g