From the figure of column chromatography given below, identify incorrect statements.

A. Compound 'c' is more polar than 'a' and 'b'

B. Compound '$$\mathrm{a}$$' is least polar

C. Compound 'b' comes out of the column before 'c' and after 'a'

D. Compound 'a' spends more time in the column

Choose the correct answer from the options given below:

The volume of $$0.02 ~\mathrm{M}$$ aqueous $$\mathrm{HBr}$$ required to neutralize $$10.0 \mathrm{~mL}$$ of $$0.01 ~\mathrm{M}$$ aqueous $$\mathrm{Ba}(\mathrm{OH})_{2}$$ is (Assume complete neutralization)

The number of species having a square planar shape from the following is __________.

$$\mathrm{XeF}_{4}, \mathrm{SF}_{4}, \mathrm{SiF}_{4}, \mathrm{BF}_{4}^{-}, \mathrm{BrF}_{4}^{-},\left[\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}\right]^{2+},\left[\mathrm{FeCl}_{4}\right]^{2-},\left[\mathrm{PtCl}_{4}\right]^{2-}$$

The standard reduction potentials at $$298 \mathrm{~K}$$ for the following half cells are given below:

$$\mathrm{NO}_{3}^{-}+4 \mathrm{H}^{+}+3 \mathrm{e}^{-} \rightarrow \mathrm{NO}(\mathrm{g})+2 \mathrm{H}_{2} \mathrm{O} \quad \mathrm{E}^{\theta}=0.97 \mathrm{~V}$$

$$\mathrm{V}^{2+}(\mathrm{aq})+2 \mathrm{e}^{-} \rightarrow \mathrm{V} \quad\quad\quad \mathrm{E}^{\theta}=-1.19 \mathrm{~V}$$

$$\mathrm{Fe}^{3+}(\mathrm{aq})+3 \mathrm{e}^{-} \rightarrow \mathrm{Fe} \quad\quad\quad \mathrm{E}^{\theta}=-0.04 \mathrm{~V}$$

$$\mathrm{Ag}^{+}(\mathrm{aq})+\mathrm{e}^{-} \rightarrow \mathrm{Ag}(\mathrm{s}) \quad\quad\quad \mathrm{E}^{\theta}=0.80 \mathrm{~V}$$

$$\mathrm{Au}^{3+}(\mathrm{aq})+3 \mathrm{e}^{-} \rightarrow \mathrm{Au}(\mathrm{s}) \quad\quad\quad \mathrm{E}^{\theta}=1.40 \mathrm{~V}$$

The number of metal(s) which will be oxidized by $$\mathrm{NO}_{3}^{-}$$ in aqueous solution is __________.