E a and ∆H values of reactions R 1 , R 2 , R 3 and R 4 carried out at the same…

E_a and ∆H values of reactions R₁, R₂, R₃ and R₄ carried out at the same temperature are as given below :
R₁ E_a = 40 kJ mol^–1, ∆H = – 80 kJ mol^–1
R₂ E_a = 20 kJ mol^–1, ∆H = – 30 kJ mol^–1
R₃ E_a = 60 kJ mol^–1, ∆H = + 40 kJ mol^–1
R₄ E_a = 30 kJ mol^–1, ∆H = + 20 kJ mol^–1
At a given temperature and assuming that the backward reactions of all these reactions have the same frequency factor, the rates of R₁, R₂, R₃ and R₄ in their respective backward reactions are in the increasing order of