Explanation:
(a) \(\mathop {{H_2}S{O_4}\,\,\,\,HCl\,\,\,\,\,\,HN{O_3}\,\,\,\,\,\,\,{\text{Total volume}}}\limits_{{N_1}{V_1}\,\,\,\,\, + \,\,{N_2}{V_2}\,\, + \,\,\,{N_3}{V_3} = N \times 1000\,ml\,\,\,} \,\,\)
\(N = \frac{{{N_1}{V_1} + {N_2}{V_2} + {N_3}{V_3}}}{{1000}}\)
\( = \frac{{50 \times 10 + 25 \times 12 + 40 \times 5}}{{1000}}\)
\(N = \frac{{500 + 300 + 200}}{{1000}} = \frac{{1000}}{{1000}} = 1\,N\)