Permanent hardness of water:
选项:
A:
is caused mainly by calcium sulfate and magnesium sulfate
B:
is caused mainly by CaSO4 and MgSO4
C:
cannot be removed by boiling
D:
can be removed by the addition of Na2CO3 while CaCO3 and MgCO3 are produced
发布时间:2024-06-05 19:02:43