When 100 ml of 1M $\mathrm{NaOH}$ solution is mixed with 10 ml of 10 M ${\mathrm{H}}_2{\mathrm{SO}}_4$, the resulting mixture will be

$\begin{array}{r}{\mathrm{N}}_{\mathrm{NaOH}}=1\times 1=1\mathrm{N}\\ {\mathrm{N}}_{{\mathrm{H}}_2{\mathrm{SO}}_4}=2\times 10=20\mathrm{N}\end{array}$

$\text{ M.eq. of }\mathrm{NaOH}=1\times 100=100$

$\text{ M.eq. of }{\mathrm{H}}_2{\mathrm{SO}}_4=20\times 10=200$

Thus $\mathrm{M}.\mathrm{eq}.$ of acid are left and therefore $\mathrm{pH}<7$, so the resulting mixture will be acidic.