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

Choose the correct statements from the following:
$A$. $Mn_2O_7$ is an oil at room temperature.
$B$. $V_2O_4$ reacts with acid to give $VO^{2+}$ ions.
$C$. $CrO$ is a basic oxide.
$D$. $V_2O_5$ does not react with acid.
Choose the correct answer from the options given below:

The spin-only magnetic moment value of the most basic oxide of vanadium among $V_2O_3$,$V_2O_4$,and $V_2O_5$ is $..... \ B.M.$ (Nearest Integer).

Stainless steel contains $..........$ $\%$ $Cr$.

The first transition series metal $M$ has the highest enthalpy of atomisation in its series. One of its aquated ion $(M^{n+})$ exists in green colour. The nature of the oxide formed by the above $M^{n+}$ ion is $:$

Which of the following statements is not correct about $Cu^{2+}$ and $Cu^{+}$?