+) Ta có: \(V_{ddNaOH}=300\left(ml\right)=0,3\left(l\right)\\ =>n_{NaOH}=V_{ddNaOH}.C_{MddNaOH}=0,3.2=0,6\left(mol\right)\\ =>m_{NaOH}=n_{NaOH}.M_{NaOH}=0,6.40=24\left(g\right)\)
+) Ta lại có: \(m_{ddNaOH}=D_{ddNaOH}.V_{ddNaOH}=1,02.300=306\left(g\right)\)
Nồng độ phần trăm của dd NaOH:
\(C\%_{ddNaOH}=\dfrac{m_{NaOH}}{m_{ddNaOH}}.100\%=\dfrac{24}{306}.100\approx7,843\%\)