设含x克H2O2. 2 H2O2 =2 H2O + O2↑ 2×34 32 x 3.2 解得 x=6.8所以质量分数w=6.8÷10=68％
2H2O2==2H2O+O2↑（二氧化锰催化）3.2g/32g/mol=0.1molH2O2为6.8g6.8/10X100%=68%
