$$\mathrm{NaCl}$$ reacts with conc. $$\mathrm{H}_2 \mathrm{SO}_4$$ and $$\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7$$ to give reddish fumes (B), which react with $$\mathrm{NaOH}$$ to give yellow solution (C). (B) and (C) respectively are ;