Question

determinati ph ul unei solutii cu volumul de 400ml care contine 1,6g de NaOH.

Answer 1

V=400 ml=0,4 l
m=1,6 g NaOH
pH=?

pOH=–lg[OH-]
CM(OH-)=νNaOH/V
νNaOH=mNaOH/MNaOH
MNaOH=23+16+1=40 g/mol
νNaOH=1,6/40=0,04 mol
CM(OH-)=0,04/0,4=0,1 M
[OH-]=0,1M

pOH=–lg 0,1=lg10=1
pOH+pH=14=> 1+pH=14=> pH=14–1
pH=13