If 100 mL of 1 M H₂SO₄ solution is mixed with 100 mL of 98% (w/w) of H₂SO₄ solution (d= 0.1 g ml^-1), then

$100 \mathrm{mL} \mathrm{of} 1 \mathrm{M} {\mathrm{H}}_2{\mathrm{SO}}_4+ 100 \mathrm{mL} (98\% , \mathrm{d}=0.1) {\mathrm{H}}_2{\mathrm{SO}}_4$

$\begin{array}{l}\Rightarrow 100\times 1\mathrm{M}+100 \mathrm{mL}\times \left(\frac{98\times 10\times 0.1}{98}\right)\\ \Rightarrow 100\times 1\mathrm{M}+100\times 1\mathrm{M}\\ \therefore \left[{\mathrm{H}}_2{\mathrm{SO}}_4\right]=\frac{100\times 1+100\times 1}{200 \mathrm{mL}}=1\mathrm{M}=98\mathrm{g}/1000 \mathrm{mL}\\ \mathrm{Mass} \mathrm{of} {\mathrm{H}}_2{\mathrm{SO}}_4=\frac{98\mathrm{g} \mathrm{x} 200 \mathrm{mL}}{1000 \mathrm{mL} }=19.6 \mathrm{g}\\ \mathrm{Concentration} \mathrm{of} \mathrm{each} \mathrm{component} \mathrm{becomes} \mathrm{half} \mathrm{of} \mathrm{the} \mathrm{initial} \mathrm{value}.\end{array}$