c
By the formula \(\mathrm{M_1}=\) density \(\times 10 \times \%\) by mass / atomic mass

\(\mathrm{M}_ 1=98 \times 1.80 \times 10 / 98=18\)

Now from formula, \(\mathrm{M_1V}_1=\mathrm{M}_ 2 \mathrm V_ 2\)

\(\mathrm{M}_1=18, \mathrm{V}_1=?, \mathrm{M}_2=0.1, \mathrm{V}_2=1 \mathrm{L}\)

So, \(\mathrm{V}_1=\mathrm{M}_2 \mathrm{V}_2 / \mathrm{M}_1\)

\(\mathrm{V}_1=0.1 \times 1 / 18=0.0055\;litters = 5.55\;ml\)