For this question, balance the chemical equation by using changes in oxidation numbers. An acidified solution of potassium dichromate(VI) can oxidise a solution containing $\text{V}^{2+}$ ions. The reaction equation is given below. $a\,\text{Cr}_2\text{O}_7^{2-} + b\,\text{V}^{2+} + c\,\text{H}^+ \rightarrow d\,\text{Cr}^{3+} + e\,\text{VO}_3^- + f\,\text{H}_2\text{O}$ What is the value of the ratio $a : b$ in the balanced equation?
- A$1 : 1$
- B$1 : 2$
- C$2 : 1$
- D$4 : 1$