The correct order of reactivity of the following benzyl halides towards reaction with KCN is :

Consider the following spectral lines for atomic hydrogen :

A. First line of Paschen series

B. Second line of Balmer series

C. Third line of Paschen series

D. Fourth line of Bracket series

The correct arrangement of the above lines in ascending order of energy is :

Aqueous HCl reacts with MnO₂(s) to form MnCl₂(aq), Cl₂(g), and H₂O(l). What is the weight (in g) of Cl₂ liberated when 8.7 g of MnO₂(s) is reacted with excess aqueous HCl solution? (Given Molar mass in g mol⁻¹ Mn = 55, Cl = 35.5, O = 16, H = 1)

Identify the metal ions among $\mathrm{Co^{2+}}$, $\mathrm{Ni^{2+}}$, $\mathrm{Fe^{2+}}$, $\mathrm{V^{3+}}$ and $\mathrm{Ti^{2+}}$ having a spin-only magnetic moment value more than 3.0 BM. The sum of unpaired electrons present in the high spin octahedral complexes formed by those metal ions is _________ .