Question

For a hypothetical reaction $A\to B,$ the activation energies for forward and backward reactions are $19kJ/$ mole and $9kJ/$ mole respectively . The heat of reactions is:

• A. $28kJ$
• B. $19kJ$
• C. $10kJ$
• D. $9kJ$

Answer 1

The correct option is C $10kJ$

Solution:-

As we know that, for a reaction,

$\Delta H=E_a$ for forward reaction $-E_a$ for backward reaction.

Given that:-

$E_a$ for forward reaction $=19kJ$

$E_a$ for backward reaction $=9kJ$

$\therefore \Delta H=19-9=10kJ$