The rate constant of a reaction is 1.5 $$\times$$ 10⁷ s^-1 at 50^oC and 4.5 $$\times$$ 10⁷ s^-1 at 100^oC. Evaluate the Arrhenius parameters A and E_a.

The ionisation constant of $$NH_4^+$$ in water is 5.6 $$\times$$ 10^-10 at 25^oC. The rate constant for the reaction of $$NH_4^+$$ and $$OH^-$$ to form NH₃ and H₂O at 25^oC is 3.4 $$\times$$ 10¹⁰ L mol^-1s^-1. Calculate the rate constant for proton transfer from water to NH₃.

At 380^oC, the half-life period for the first order decomposition of H₂O₂ is 360 min. Calculate the time required for 75% decomposition at 450^oC.

A first order reaction A $$\to$$ B, requires activation energy of 70 kJ mol^-1. When 20% solution of A was kept at 25^oC for 20 minutes, 25% decomposition tooks place. What will be the percentage decomposition in the same time in a 30% solution maintained at 40^oC? Assume that activation energy remains constant in this range of temperature.