Question

$Fe{Cr}_2{O}_4+{Na}_2{CO}_3+O_2\underset{}{\overset{Fusion}{\to }}\left[X\right]\underset{H_{2}O}{\overset{H^{+}}{\to }}\left[Y\right]\underset{H_2{O}_2}{\overset{H^{+}}{\to }}\left[Z\right]$

Which of the following statements is true for the compounds $\left[X\right],\left[Y\right]$ and $\left[Z\right]$?

• A. In all three compounds, the chromium is in $+6$ oxidation state
• B. $\left[Z\right]$ is a deep blue-violet colored compounds which decomposes rapidly in aqueous solution into ${Cr}^{3+}$ and dioxygen
• C. Saturated solution of $\left[Y\right]$ gives bright orange compound, chromium anhydride, with concentrated $H_2{SO}_4$
• D. All of the above

Answer 1

Answer: (D)

All of the above

$FeC{r}_2{O}_4+N{a}_{2}C{O}_3+O_2\stackrel{Fusion}{\to }N{a}_{2}Cr{O}_4\underset{H_{2}O}{\overset{H^{+}}{\to }}C{r}_2{O}_7^{2-}\underset{H_2{O}_2}{\overset{H^{+}}{\to }}\underset{\text{deep blue coloured}}{CrO(O_2{)}_2}$

$CrO(O_2{)}_2$ decomposes rapidly in aqueous solution into $C{r}^{3+}$ and oxygen.

Saturate solution dichromate ion fives bright orange compound with conc. sulphuric acid.