Which alloy is used for making coins?

State the uses of zinc and iron.

Highest fluoride and highest oxide of $Mn$ are respectively

Write two uses of $KMnO_4$ and $K_2Cr_2O_7$.

Given below are some statements about $Mn$ and $Mn_2O_7$. Identify the correct statements:
$A$. $Mn$ forms the oxide $Mn_2O_7$ in which $Mn$ is in its highest oxidation state.
$B$. Oxygen stabilizes the $Mn$ in higher oxidation states by forming multiple bonds with $Mn$.
$C$. $Mn_2O_7$ is an ionic oxide.
$D$. The structure of $Mn_2O_7$ consists of one bridged oxygen.
Choose the correct answer from the options given below:

$CrO_3$ dissolves in aqueous $NaOH$ to give: