Question

Using the data provided, calculate the multiple bond energy ($kJ{mol}^{-1}$) of $C\equiv C$ bond in $C_2{H}_2$. That energy is (take the bond energy of a $C-H$ bond as $350kJ{mol}^{-1}$):
$2C\left(s\right)+H_2\left(g\right)⟶C_2{H}_2\left(g\right);\Delta H^{}=225kJ{mol}^{-1}$
$2C\left(s\right)⟶2C\left(g\right);\Delta H^{}=1410kJ{mol}^{-1}$
$H_2\left(g\right)⟶2H\left(g\right);\Delta H^{}=330kJ{mol}^{-1}$

• A. $1165$
• B. $837$
• C. $865$
• D. $815$

Answer 1

The correct option is D $815$

$\Delta H_R=(bondenergy{)}_R-(bondenergy{)}_P$

$225=\left(\right[1410+330]-[\Delta H_{c\equiv c}+2\ast 350\left]\right)$

$\therefore \Delta H_{c\equiv c}=815KJ/mol$