Answer
Please see the work below
Work Step by Step
Effect of catalyst on
(a) $Activation$ $Energy$ : Catalyst decreases the activation energy, hence make the reaction faster.
(b) $Reaction$ $Mechanism$ : It provide surface for the reaction to take place, hence it get involved in the reaction and changes its mechanism.
(c) $Rate$ $of$ $forward$ $step$ : Catalyst relatively increases the rate of the forward reaction, it comes from the fact that reaction becomes faster
(d) $Rate$ $of$ $backward$ $step$ : Rate of backward step also increases equally as that of rate of forward step as catalyst doesn't change the value of equilibrium constant
