Question

Assertion :Bond order for ${CO}^{+}$ is more than bond order in $CO$ whereas bond order in $N_2^{+}$ is less than $N_2$ whereas both are isoelectronics. Reason: Both have same bond order.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Assertion is incorrect but Reason is correct

Answer 1

The correct option is C Assertion is correct but Reason is incorrect

Assertion:

Bond order of ${CO}^{+}$= $\frac{9-4}{2}=\frac{5}{2}=2.5$

Bond order of $CO$=$\frac{10-4}{2}=3$

So, bond order of ${CO}^{+}$ is less than CO.

Bond order of $N_2$= $\frac{10-4}{2}=3$

Bond order of $N_2^{+}=\frac{9-4}{2}=2.5$

Again, $N_2^{+}$ has lesser bond order than $N_2$

But both the sets are iso electronic with each other, i.e, ${CO}^{+}$ and $N_2^{+}$. Both have 13 electrons in its molecular orbital, and $N_2$ and CO, both have 14 electrons in its molecular orbital.

Reason:
Both ${CO}^{+}$ and $N_2^{+}$ have same bond order=2.5

and

Both $CO$ and $N_2$ have same bond order=3

Ans: Assertion is incorrect since according to the statement given, ${CO}^{+}$ has more 6.0 than CO, but that's wrong, the reason is correct and assertion is incorrect.