' X ' is the number of acidic oxides among $\mathrm{VO}_2$, $\mathrm{V}_2 \mathrm{O}_3, \mathrm{CrO}_3, \mathrm{~V}_2 \mathrm{O}_5$ and $\mathrm{Mn}_2 \mathrm{O}_7$. The primary valency of cobalt in $\left[\mathrm{Co}\left(\mathrm{H}_2 \mathrm{NCH}_2 \mathrm{CH}_2 \mathrm{NH}_2\right)_3\right]_2\left(\mathrm{SO}_4\right)_3$ is Y. The value of $\mathrm{X}+\mathrm{Y}$ is :

• Correct answer
  A

  5
• B

  4
• C

  2
• D

  3

Solution

$\begin{aligned} & \mathrm{CrO}_3=\text { Acidic } \\ & \mathrm{Mn}_2 \mathrm{O}_7=\text { Acidic } \\ & \therefore \mathrm{x}=2\end{aligned}$

$\begin{aligned} & \therefore \text { Primary valency }=3 \\ & \therefore \mathrm{x}+\mathrm{y}=5\end{aligned}$

Hence, the correct answer is option: 'A'.