A pair of compounds having the same boiling points are
Identify A, B and C in the sequence.
$$\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{Br} \underset{\text { Alc. }}{\stackrel{\mathrm{KCN}}{\longrightarrow}} A \stackrel{\mathrm{LiAlH}_4}{\longrightarrow} B \stackrel{\mathrm{HNO}_2}{\longrightarrow} C$$
$$\begin{aligned} & \mathrm{CH}_3-\mathrm{CH}=\mathrm{CH}-\mathrm{CH}_2 \mathrm{OH} \stackrel{\mathrm{PCC}}{\longrightarrow} \\\\ & \mathrm{CH}_3-\mathrm{CH}=\mathrm{CH}-\mathrm{CHO} \end{aligned}$$
Hybridisation change involved at $$\mathrm{C}$$-$$1$$ in the above reaction.
If a didentate ligand ethane-1, 2-diamine is progressively added in the molar ratio en : Ni :: 1: 1, 2 : 1, 3 : 1 to $$\left[\mathrm{Ni}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}$$ aq solution, following co-ordination entities are formed.
I. $$\left[\mathrm{Ni}\left(\mathrm{H}_2 \mathrm{O}\right)_4 \mathrm{en}\right]^{2+}(a q)$$ - pale blue
II. $$\left[\mathrm{Ni}\left(\mathrm{H}_2 \mathrm{O}\right)_2(\mathrm{en})_2\right]^{2+}(\mathrm{aq})$$ - blue/purple
III. $$\left[\mathrm{Ni}(\mathrm{en})_3\right]^{2+}(\mathrm{aq})$$ - violet
The wavelength in $$\mathrm{nm}$$ of light absorbed in case of I and III are respectively