Which among the following statements is incorrect for manganate and permanganate ions?

In the scheme given below,$X$ and $Y$,respectively,are:
$\text{Metal halide} \xrightarrow{\text{aq. NaOH}} \text{White precipitate } (P) + \text{Filtrate } (Q)$
$P \xrightarrow[\text{heat}]{\text{aq. } H_2SO_4, PbO_2 (\text{excess})} X (\text{a coloured species in solution})$
$Q$ $\xrightarrow[\text{warm}]{\text{MnO(OH)}_2, \text{Conc. } H_2SO_4} Y (\text{gives blue-coloration with KI-starch paper})$

Identify the reactions in which dichromate acts as an oxidising reagent.
$I$. $Cr_2O_7^{2-} + 6Fe^{2+} + 14H^{+} \longrightarrow 2Cr^{3+} + 6Fe^{3+} + 7H_2O$
$II$. $Cr_2O_7^{2-} + 2OH^{-} \longrightarrow 2CrO_4^{2-} + H_2O$
$III$. $Cr_2O_7^{2-} + 6I^{-} + 14H^{+} \longrightarrow 2Cr^{3+} + 3I_2 + 7H_2O$
$IV$. $Na_2Cr_2O_7 + 2KCl \longrightarrow K_2Cr_2O_7 + 2NaCl$

Which of the following is a product of the first step and is used as a reactant in the next step for the manufacture of $K_{2}Cr_{2}O_{7}$ from concentrated chromite ore?

Assertion : Coloured cations can be identified by borax bead test.
Reason : Transparent bead $(NaBO_2 + B_2O_3)$ forms coloured bead with coloured cation.

Which of the following is used for making railway tracks?