Question

The following graph is given, between total energy and distance between the two nuclei for species $H _{2}{ }^{+}, H _{2}, He _{2}{ }^{+} \,\&\, He _{2}$, which of the following statements is correct :

• A. $He _{2}^{+}$is more stable than $H _{2}{ }^{+}$.
• B. Bond dissociation energy of $H _{2}^{+}$is more than bond dissociation energy of $He _{2}^{+}$.
• C. Since bond orders of $He _{2}^{+}$and $H _{2}^{+}$are equal hence both will have equal bond dissociation energy.
• D. Bond length of $H _{2}^{+}$is less than bond length of $H _{2}$.

Answer 1

Answer: (B)

From the graph
$B.E.$ of $H _{2}> B.E.$ of $H _{2}^{+}>B.E$ of $He _{2}^{+}> BE$ of $He _{2}$
where $BE =$ bond energy or bond dissociation energy and
$B.L. $ of $H _{2}< B.L.$ of $H _{2}^{+} < B.L.$ of $He _{2}^{+} where $B.L.$ bond length
so stability order $= H _{2}> H _{2}^{+}> He _{2}^{+}> He _{2}$