a.
$NaOH→Na^++OH^-$
-$[OH^-]=[NaOH]=0,1.0,0012=1,2.10^{-4}(M)$
-$[H^+]=\frac{10^{-14}}{1,2.10^{-4}}≈8,33.10^{-14}(M)$
b.
$HCl→H^++Cl^-$
$H_2SO_4→2H^++SO_4^{2-}$
-$[H^+]=[HCl]+2.[H_2SO_4]=0,3.0,0024+2.0,3.0,00036=9,36.10^{-4}(M)$
-$[OH^-]=\frac{10^{-14}}{9,36.10^{-4}}≈1,068.10^{-11}(M)$
c.
$NaOH→Na^++OH^-$
$Ca(OH)_2→Ca^{2+}+2OH^-$
-$[OH^-]=[NaOH]+2.[Ca(OH)_2]=0,04.0,003+2.0,1.0,0007=2,6.10^{-4}(M)$
-$[H^+]=\frac{10^{-14}}{2,6.10^{-4}}≈3,846.10^{-11}(M)$