The correct order of Lewis acidic character of boron trihalides is

The acidic oxide from the following is

A nitrogen oxide that forms "in situ" when dilute $\mathrm{FeSO}_4$ is treated with aqueous solution of nitrate ion and then careful addition of conc. $\mathrm{H}_2 \mathrm{SO}_4$ along the sides of test tube, is

$$ \text { Match the following. } $$

$$ \begin{array}{lcll} \hline & \text { Column-I (Molecule) } & & \text { Column-II (Colour) } \\ \hline \text { (A) } & \mathrm{F}_2 & \text { (I) } & \text { Red } \\ \hline \text { (B) } & \mathrm{Cl}_2 & \text { (II) } & \text { Violet } \\ \hline \text { (C) } & \mathrm{Br}_2 & \text { (III) } & \text { Yellow } \\ \hline \text { (D) } & \mathrm{I}_2 & \text { (IV) } & \text { Greenish yellow } \\ \hline \end{array} $$

$$ \text { The correct match is } $$