Ta có: \(n_{Na_2O}=\dfrac{12,4}{62}=0,2\left(mol\right)\)
PTHH: Na2O + H2O ---> 2NaOH
Theo PT: \(n_{NaOH}=2.n_{Na_2O}=2.0,2=0,4\left(mol\right)\)
Đổi 800ml = 0,8 lít
=> \(V_{dd_{NaOH}}=V_{H_2O}=0,8\left(lít\right)\)
=> \(C_{M_{NạOH}}=\dfrac{0,4}{0,8}=0,5M\)
\(n_{Na_2O}=\dfrac{12,4}{62}=0,2mol\)
\(Na_2O+H_2O\rightarrow2NaOH\)
0,2 0,4
\(C_{M_{ddNaOH}}=\dfrac{0,4}{0,8}=0,5M\)