Which of the following aqueous solutions absorbs nitric oxide in significant amounts?

$KMnO_4$ decomposes on heating at $513 \ K$ to form $O_2$ along with

Write about the utility of $d$- and $f$-block elements and their compounds. Or describe the following uses of $d$- and $f$-block elements and their compounds: $(i)$ In iron/steel $(ii)$ As pigments $(iii)$ In batteries $(iv)$ In coinage $(v)$ As catalysts.

Potassium permanganate on heating at $513 \ K$ gives a product which is :

$K_2Cr_2O_7 + H_2O_2 \xrightarrow{H^{+}} $

Which transition metal oxide among the following has electrical conductivity similar to that of copper?