A hydrogenation reaction is carried out at 500 K. If the same reaction is carried out in the presence of a catalyst at the same rate, the temperature required is 400 K. Calculate the activation energy of the reaction if the catalyst lowers the activation barrier by 20 kJ mol^-1.

The following electrochemical cell has been set up.
Pt(1) | Fe³⁺, Fe²⁺ (a = 1) | Ce⁴⁺, Ce³⁺ (a=1) | Pt(2)
E^o (Fe³⁺, Fe²⁺) = 0.77 V; E^o (Ce⁴⁺, Ce³⁺) = 1.61 V
If an ammeter is connected between the two platinum electrodes, predict the direction of flow of current. Will the current increase or decrease with time?

Copper sulphate solution (250 mL) was electrolysed using platinum anode and a copper cathode. A constant current of 2mA was passed for 16 minutes. It was found that after electrolysis the absorbance of the solution was reduced to 50% of its original value. Calculate the concentration of copper sulphate in the solution to begin with.

To 500 cm³ of water, 3.0 $$\times$$ 10^-3 kg of acetic acid is added. If 23% of acetic acid is dissociated, what will be the depression in freezing point? Kf and density of water are 1.86 K kg^-1 mol^-1 and 0.997 g cm^-3, respectively