Question

Assertion : Bond order of $H_2^{+}\text{is}\mathrm{0.5.}$
Reason : Electrons are removed from the antibonding molecular orbital from $H_2.$

• A. Assertion is true and reason is incorrect explanation for assertion
• B. Assertion is false and reason is incorrect explanation for assertion
• C. Assertion is true and reason is correct explanation for assertion
• D. Assertion is false and reason is correct explanation for assertion

Answer 1

The correct option is A Assertion is true and reason is incorrect explanation for assertion

$H_2^{+}=\sigma 1s^1$
$\text{Bond order}=\frac{\text{Bonding electrons - Antibonding electrons}}{2}=\frac{1-0}{2}=0.5$

Hydrogen molecule cation $H_2^{+}$: This molecule ion has only one electron. This electron is present in lowermost molecular orbital i.e, $\sigma 1s.$ So electronic configuration of $H_2^{+}$ is :$(\sigma 1s{)}^1$ and
$H_2:(\sigma 1s{)}^2$
So, an electron is removed from the bonding orbital of $H_2$ to form $H_2^{+}$ ion.