Nồng độ dung dịch NaOH là:
\(C\%_{NaOH}=\frac{m_{NaOH}}{m_{ddNaOH}}.100\%=\frac{30}{170+30}.100\%=15\%\)
Good luck!
mdd = 30+170 = 200 g
C%NaOH = 30/200*100% = 15%
\(m_{ddNaOH}=30+170=200\left(g\right)\)
\(\Rightarrow C\%_{NaOH}=\frac{30}{200}\times100\%=15\%\)