$A$ hard and resistant metal alloy generally used in the tip of the nib of a fountain pen is

Presence of $Cr$ in steel makes it

The yellow colour solution of $Na_2CrO_4$ changes to orange-red on passing $CO_2$ gas due to the formation of

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

Provide the structures for:
$1.$ $MnO_4^{-}$
$2.$ $MnO_4^{2-}$

The amphoteric oxide among $V_2O_3$,$V_2O_4$,and $V_2O_5$ upon reaction with alkali leads to the formation of an oxide anion. The oxidation state of $V$ in the oxide anion is: