Question: On balancing the given redox reaction,

$$ \mathrm{aCr}_2 \mathrm{O}_7^{2-}+\mathrm{bSO}_3^{2-}(\mathrm{aq})+\mathrm{cH}^{+}(\mathrm{aq}) \rightarrow 2 \mathrm{aCr}^{3+}(\mathrm{aq})+\mathrm{bSO}_4^{2-}(\mathrm{aq})+\frac{\mathrm{c}}{2} \mathrm{H}_2 \mathrm{O}(\ell) $$ the coefficients a, b and c are found to be, respectively -

A) $3,8,1$

B) $1,8,3$

C) $8,1,3$

D) $1,3,8$

Answer: $1,3,8$