Find the correct matches.
\(\begin{array}{|l|l|l|l|} \hline \text{A} & \mathrm{Cr}_2 \mathrm{O}_7^{2-} & \mathrm{P} & \text{is predominantly a basic compound.} \\ \hline \text{B} & \mathrm{FeCr}_2 \mathrm{O}_4 & \mathrm{Q} & \text{is predominantly an acidic compound.} \\ \hline \text{C} & \mathrm{CrO}_3 & \mathrm{R} & \text{forms yellow chromate on reaction with } \mathrm{Na}_2 \mathrm{CO}_3 \text{ in air.} \\ \hline \text{D} & \mathrm{CrO} & \mathrm{S} & \text{is interconvertible with } \mathrm{MO}_4^{2-} \text{ depending on the pH of the medium.} \\ \hline \end{array}\)

1. A \(\mathrm{A}=\mathrm{R} \quad \mathrm{B}=\mathrm{S} \quad \mathrm{C}=\mathrm{P} \quad \mathrm{D}=\mathrm{Q}\)
2. B \(\mathrm{A}=\mathrm{R} \quad \mathrm{B}=\mathrm{Q} \quad \mathrm{C}=\mathrm{S} \quad \mathrm{D}=\mathrm{P}\)
3. C \(\mathrm{A}=\mathrm{S} \quad \mathrm{B}=\mathrm{R} \quad \mathrm{C}=\mathrm{Q} \quad \mathrm{D}=\mathrm{P}\)
4. D \(\mathrm{A}=\mathrm{S} \quad \mathrm{B}=\mathrm{R} \quad \mathrm{C}=\mathrm{P} \quad \mathrm{D}=\mathrm{Q}\)