The chromate ion in acidic medium changes to . (write name)

Define the oxidation states of $\mathrm{Mn}$ in product of the given reaction

$3{ \mathrm{K}}_2{\mathrm{MnO}}_4+2{\mathrm{H}}_2\mathrm{O}+4{\mathrm{CO}}_2\to 2\mathrm{X}+\mathrm{Y}+4{\mathrm{KHCO}}_3$

If the oxidation state of $\mathrm{Mn}$ in product $\mathrm{X}$ and $\mathrm{Y}$ are ${\mathrm{n}}_1$ and ${\mathrm{n}}_2$ respectively. Then find out the value of $\left({\mathrm{n}}_1+{\mathrm{n}}_2\right)-$

Find number of metal ion which can produce high spin and low spin octahedral complex:

${\mathrm{Sc}}^{+3},{\mathrm{Ti}}^{+3},{ \mathrm{V}}^{+3},{\mathrm{Cr}}^{+3},{\mathrm{Mn}}^{+3},{\mathrm{Fe}}^{+3},{\mathrm{Co}}^{+3},{\mathrm{Ni}}^{+2}$

Find the number of following chemical spieces which decolorize acidic solution of ${\mathrm{KMnO}}_4$

$\mathrm{KI},{\mathrm{Na}}_2{\mathrm{SO}}_3,{\mathrm{Na}}_2{\mathrm{SO}}_4,\mathrm{NaCl},{\mathrm{O}}_3$