Q1 / 180 · KCET 2025 · Chemistry

Match List-I with List-II and select the correct option: \begin{array}{|l|l|l|l|}\hline & \text{List-I (Molecule / ion} & & \text{List-II (Bond order)} \\\hline \text{1}. & \text{NO} & \text{(i)} & \text {15} \\\hline \text{2.} & \text{CO} & \text{(ii)} & \text{2.0} \\\hline \text{3.} & \mathrm{O}_2^{-} & \text{(iii)} & \text{2.5} \\\hline \text{4.} & \mathrm{O}_2 & \text{(iv)} & \text{3.0} \\\hline\end{array}

  • Correct answer
    A
    a-iii, b-iv, c-i, d-ii
  • B
    a-i, b-iv, c-iii, d-ii
  • C
    a-ii, b-iii, c-iv, d-i
  • D
    a-iv, b-iii, c-ii, d-i

Solution

Bond order $=\frac{1}{2}$ [no. of bonding - no. of bonding electrons] For NO molecule $\begin{aligned} & \mathrm{BO}=(8-3) / 2=2.5 \\ & \mathrm{CO}-\frac{1}{2}[10-4]=3.0 \\ & \mathrm{O}_2^{-1}-\frac{1}{2}[6-3]=1.5 \\ & \mathrm{O}_2-\frac{1}{2}[6-2]=2.0 \end{aligned}$

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

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