1)
Ta có:
\({m_{HCl}} = 300.14,6\% = 43,8{\text{gam}} \to {{\text{m}}_{dd{\text{ HCl 7}}{\text{,3\% }}}} = \frac{{43,8}}{{7,3\% }} = 600{\text{ gam}} \to {{\text{m}}_{{H_2}O}} = 600 - 300 = 300{\text{ gam}}\)
2)
Ta có:
\({m_{{H_2}O}} = 150.(100\% - 15\% ) = 127,5{\text{ gam}}\)
Trong dung dịch NaCl 20% thì chứa 80% nước.
\( \to {m_{dd{\text{ NaCl 20\% }}}} = \frac{{127,5\% }}{{80\% }} = 159,3575{\text{ gam}} \to {{\text{m}}_{NaCl}} = 159,375 - 150 = 9,375{\text{ gam}}\)