Question

The oxidation states of transition metal atoms in${\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7,{\mathrm{KMnO}}_4\mathrm{and}{\mathrm{K}}_2{\mathrm{FeO}}_4$, respectively, are $\mathrm{x},\mathrm{y}\mathrm{and}\mathrm{z}$. The sum of $\mathrm{x},\mathrm{y}\mathrm{and}\mathrm{z}$ is

Answer 1

Step 1: Identify transitional metal in given compounds

• The transitional metals in ${\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7,{\mathrm{KMnO}}_4\mathrm{and}{\mathrm{K}}_2{\mathrm{FeO}}_4$ are $\mathrm{Cr},\mathrm{Mn}\mathrm{and}\mathrm{Fe}$ .

Step 2: Compute the oxidation state of transitional atoms

• The oxidation state of $\mathrm{Cr}$ in ${\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$ is,
• $\begin{array}{rcl}2\left(+1\right)+2x+7\left(-2\right)& =& 0\\ 2x& =& 12\\ x& =& +6\end{array}$
• And the oxidation state of $\mathrm{Mn}$ in ${\mathrm{KMnO}}_4$ is,
• $\begin{array}{rcl}\left(+1\right)+y+4\left(-2\right)& =& 0\\ y& =& +7\end{array}$
• Similarly, the oxidation of $\mathrm{Fe}$ in ${\mathrm{K}}_2{\mathrm{FeO}}_4$ is,
• $\begin{array}{rcl}2\left(+1\right)+z+4\left(-2\right)& =& 0\\ z& =& +6\end{array}$

Step 3: Compute the sum of $\mathrm{x},\mathrm{y}\mathrm{and}\mathrm{z}$

• $\begin{array}{rcl}x+y+z& =& 6+7+6\\ & =& 19\end{array}$

Hence, the sum of $\mathrm{x},\mathrm{y}\mathrm{and}\mathrm{z}$ is $19$.