从资料上查到:20%的硫酸其密度是1.14g/ml ；98%的硫酸其密度是1.84g/ml ；所以配250ml20%的硫酸溶液需浓硫酸体积v是:250ml * 1.14g/ml * 20%=1.84g/ml * v * 98%v=250*1.14*0.20/1.84*0.98≈31.6ml .需要水的体积是...