When acidified $K_2Cr_2O_7$ reacts with $H_2O_2$,a blue-coloured solution is obtained. This blue colour is due to the formation of:

$Fe_2Cr_2O_4 + Na_2CO_3 + O_2$ $\xrightarrow{\text{Fusion}} [X]$ $\xrightarrow[H_2O]{H^{+}} [Y]$ $\xrightarrow{H_2O_2/H^{+}} [Z]$
Which of the following statements is true for the compounds $[X]$,$[Y]$,and $[Z]$?

Compounds of $d-$block elements can stabilize in higher oxidation states only with $F$ and $O$. Which statement is incorrect?

Paris green is

The false statement about iron $(III)$ hydroxide is that

Which of the following is amphoteric?