Question

cho 0,062g Na2O vào 200ml NaOH 0,01M thu đc dd X .pH dd X =?

Answer 1

Na2O + H2O -> 2NaOH

10^-3.....................2.10^-3 (mol)

n_Na2O = 10^-3 (mol)

\(\Sigma n_{NaOH}=\) \(\frac{200}{1000}.0,01+2.10^{-3}=4.10^{-3}\) (mol)

\(\left[NaOH\right]=0,02\left(M\right)\) => pH \(\approx12,3\)

Answer 2

nNa2O=0,001 mol
nNaOH =0,01.0,2=0,002 mol
Na2O + H2O = 2NaOH
0,001..................0,002
nNaOH =0,002 mol
=> nNaOH tổng =0,002+0,002=0,004 mol
=> p(OH) = 1,7
=> pH = 14-1,7=12,3