Δ H = 10 kJ/mol 30 kJ/mol and 40 kJ/mol 10 kJ/mol Yes; because catalyst lowers the activation energies of both forward and backward reaction.

Δ H = –10 kJ/mol – 30 kJ/mol and 40 kJ/mol 20 kJ/mol No; because catalyst lowers the activation energy of forward reaction at a greater extent than the activation energy of backward reaction.

Δ H = –30 kJ/mol 100 kJ/mol and 110 kJ/mol 90 kJ/mol No; because catalyst lowers the activation energy of forward reaction but increases the activation energy of backward reaction.

Δ H = –100 kJ/mol (ii) For the forward and backward reaction the activation energy of the reaction respectively are – 140 kJ/mol and 100 kJ/mol (iii) What is the energy of activation energy for the reaction in the presence of catalyst? 100 kJ/mol (iv) Will the catalyst influence the forward and backward reaction at equal extent ? Yes; because catalyst lower the activation energies of both forward and backward reaction at the extent of 30 kJ/mol.