\(n_{NaOH}=0,25.0,2=0,05\left(mol\right)\)
\(PTHH:2NaOH+H_2SO_4\rightarrow Na_2SO_4+2H_2O\)
__________0,05 ______0,025____________________
\(SO_2+Br_2+2H_2O\rightarrow2HBr+H_2SO_4\)
\(\Rightarrow n_{Br2}=n_{H2SO4}=0,025\left(mol\right)\)
\(\Rightarrow CM_{Br2}=\frac{0,025}{0,5}=0,05M\)