(1)m(H2SO4)=0.5mol×98g/mol=49g,N(O)=0.5mol×4×NA/mol=2NA,
由方程式H2SO4+2NaOH=Na2SO4+2H2O可知,需要1molNaOH,
故答案为:49;2NA;1;
(2)n=
,则M=0.1L 22.4L/mol
=m n
=28g/mol,则该气体的相对分子质量为28,故答案为:28;0.125g
0.1L 22.4L/mol
(3)n(HCl)=
=0.1mol,2.24L 22.4L/mol
c(HCl)=
=1mol/L,0.1mol 0.1L
ω(HCl)=
×100%=3.65%,0.1mol×36.5g/mol 100mL×1g/mL
故答案为:1mol/L; 3.65%.