Question

which of the following pairs is expected to have the same bond order
1 NO and CN–
2 CN– and NO+
3 CN– and CN+
4 O² and CN–
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Answer 1

The MOST EASY WAY to solve this type of ques is to calculate the electrons in the pairs.

• same no. of electrons will result in same MOT distribution, which ultimately gives same bond order.

Let's calculate the electrons:

$\bf 1.\: NO\: and\: CN^{-1}$

• NO = 7+8= 15 e-
• CN- = 6+7+1 = 14 e-

$\bf 2.\: CN^{-1}\: and\: NO^{+1}$

• CN- = 6+7+1 = 14 e-
• NO+ = 7+8-1 = 14 e-

$\bf 3.\: CN^{-1}\: and\: CN^{+1}$

• CN- = 6+7+1 = 14 e-
• CN+ = 6+7-1 = 12 e-

$\bf 4.\: O_2\: and\: CN^{-1}$

• O2 = 8+8=16 e-
• CN- = 6+7+1=14 e-

★ so, from above calculations we can say that CN- and NO+ has same bond order.