Q1 / 60 · JEE Advanced 2014 (Paper 2) · Chemistry

Assuming $2 s - 2 p$ mixing is NOT operative, the paramagnetic species among the following is

Solution

Assuming that no 2s-2p mixing takes place
(i)

B e_{2} \to σ 1 s^{2}, σ^{*} 1 s^{2}, σ 2 s^{2}, σ^{*} 2 s^{2}

(diamagnetic)
(ii)

B_{2} \to σ 1 s^{2}, σ^{*} 1 s^{2}, σ 2 s^{2}, σ^{*} 2 s^{2}, σ 2 p_{z}^{2}, \begin{matrix} π 2 p_{x}^{0} \\ π 2 p_{y}^{0} \end{matrix}

(diamagnetic)
(iii)

C_{2} \to σ 1 s^{2}, σ^{*} 1 s^{2}, σ 2 s^{2}, σ^{*} 2 s^{2}, σ 2 p_{z}^{2}, \begin{matrix} π 2 p_{x}^{1} \\ π 2 p_{y}^{1} \end{matrix}, \begin{matrix} π^{*} 2 p_{x}^{0} \\ π^{*} 2 p_{y}^{0} \end{matrix}, σ^{*} 2 p_{z}^{0}

(paramagnetic)
(iv)

N_{2} \to σ 1 s^{2}, σ^{*} 1 s^{2}, σ 2 s^{2}, σ^{*} 2 s^{2}, σ 2 p_{z}^{2}, \begin{matrix} π 2 p_{x}^{2} \\ π 2 p_{y}^{2} \end{matrix}, \begin{matrix} π^{*} 2 p_{x}^{0} \\ π^{*} 2 p_{y}^{0} \end{matrix}, σ^{*} 2 p_{z}^{0}

(diamagnetic)

Hence, the correct answer is option: 'C'.