Two molecules A and B collide, but no reaction occurs. Which of the following MUST be true?

${{\rm{N}}_2}\left( {\rm{g}} \right) + 3{{\rm{H}}_2}\left( {\rm{g}} \right)\;\leftrightharpoons\;2{\rm{N}}{{\rm{H}}_3}\left( {\rm{g}} \right) + 22\;{\rm{kcal}}$.

The activation energy for the forward reaction is $50{\rm{ }}\;kcal.$ What is the activation energy for the backward reaction?

Combustion of carbon is exothermic, but coal stored in coal depots does not burn automatically because of:

For producing the effective collision, the colliding molecules must possess

The ${E_a}$ of exothermic reaction, $A o B$ is $80\,\,KJ/mol$. Heat of reaction is $20\,\,KJ/mol$. ${E_a}$ for the reaction $B o A$ will be

The minimum energy a molecule should posses in order to enter into a fruitful collision is known as

The rate of a specific chemical reaction is significantly increased by the introduction of a catalyst. Which of these factors associated with the reaction remains unaltered?

For an endothermic reaction

The threshold energy of a chemical reaction depends upon:

The pre-exponential factor (A) in the Arrhenius equation is related to the:

For an endothermic reaction where, $\Delta H$ represents the enthalpy of the reaction in $kJ/mol,$ the minimum value for the energy of activation will be