Question

please I need full explanation for this question

A common way to describe the bonding energy curve for secondary bonding is the "6-12" potential. which states the bonding energy, E-At·Write the expression that best represent the equilibrium bond length 18 2 2 t LA12 8 1- h

Answer 1

$E = -\frac{A}{r^6}+\frac{B}{r^{12}}$

Equilibrium bond length is the point where Bond energy is minimum.

Which means derivative of bond energy with respect to r = 0

$\frac{dE}{dr} = 0$

$\frac{dE}{dr} = \frac{d}{dr}[ -\frac{A}{r^6}+\frac{B}{r^{12}}]$

$\frac{d}{dr}(\frac{1}{r^n}) = -\frac{n}{r^{n+1}}$

$\frac{dE}{dr} = \frac{6A}{r^7}-\frac{12B}{r^{13}}=0$

$\frac{r_e^{13}}{r_e^7}=\frac{12B}{6A}$

$r_e^6 =\frac{6B}{A}$

Equilibrium bond length is given by:

$r_e =(\frac{6B}{A})^{1/6}$