1.NaOH的质量为50*8%=4g
2.pH=7,说明NaOH与稀盐酸恰好完全反应.
设x生成NaCl的质量为x.
NaOH+HCl=NaCl+H2O
40 58.5
4g x
40/4=58.5/x
x=5.85g