问题
选择题
将a mol钠和a mol铝一同投入m g足量水中,所得溶液密度为d g·mL-1,该溶液的溶质质量分数为( )
A.%
B.%
C.a/2%
D.3a/2%
答案
答案:C
由2Na+2H2O2NaOH+H2↑,2Al+2NaOH+2H2O
2NaAlO2+3H2↑可知:
2Na — 2NOH — H2↑
a mol a mol a/2 mol
2Al — 2NaOH — 2NaAlO2 — 3H2↑
a mol a mol a mol 3a/2 mol