Question

4)Dimerisation of NO2 is an exothermic reaction. If enthalpy of reaction is ∆H, then the minimum value of activation energy for forward reaction (Ea) will be

Equal to ∆H

Equal to zero

Greater than ∆H

Greater than threshold energy​

Answer 1

Answer:

It should be greater than deltH

Explanation:

hope it will help you

Answer 2

Answer:

The minimum value of activation energy for the forward reaction (Ea) will be greater than ∆H.

Explanation:

The dimerization of NO₂ is as follows,

$2NO_2(g)\rightarrow N_2O_4(g)$

The dimerization of NO₂ is exothermic in nature. So, the overall enthalpy of the reaction (∆H) will be negative. i.e.

                                       $\Delta H=-ve$        (1)

And the relation between the enthalpy of the reaction  and activation energy is given as,

                                 $-\Delta H=E_f-E_b$     (2)

Where,

∆H=enthalpy change of the reaction

$E_f$=activation energy in the forward direction

$E_b$=activation energy in the backward direction

So,

                         $E_f=-\Delta H+E_b$     (3)

Hence, the minimum value of activation energy for the forward reaction (Ea) will be greater than ∆H.