278) The half time period t_(1⁄2) is independent of the initial concentration of reactant when the order of reaction is:

279) The rate constant of a zero order reaction is 0.2 mol dm⁻³hr⁻¹ of the concentration of the reactant after 30 minutes is 0.05 mol dm⁻³ then its initial concentration would be:

280) Collision theory is applicable to :

281) The half life of a second order reaction is:

282) 16.0 gm of a radioactive substance is reduced to 0.50 g after 2 hours. Then the half life of the radioactive substance is: