If the time required for half change is inversely proportional to the square of initial concentration and the velocity depends on the units in which the concentration term is expressed, then the order of reaction is

A first order gaseous phase reaction is catalysed by a non-porous solid. The kinetic rate constant and the external mass transfer co-efficients are k and $${{\text{k}}_{\text{g}}}$$ respectively. The effective rate constant (k_eff) is given by

A. $${{\text{k}}_{\text{e}}}{\text{ff}} = {\text{k}} + {{\text{k}}_{\text{g}}}$$

B. $${{\text{k}}_{\text{e}}}{\text{ff}} = \frac{{{\text{k}} + {{\text{k}}_{\text{g}}}}}{2}$$

C. $${{\text{k}}_{\text{e}}}{\text{ff}} = {\left( {{\text{k}}{{\text{k}}_{\text{g}}}} \right)^{\frac{1}{2}}}$$

D. $$\frac{1}{{{{\text{k}}_{\text{e}}}{\text{ff}}}} = \frac{1}{{\text{k}}} + \frac{1}{{{{\text{k}}_{\text{g}}}}}$$

The half life period of a first order reaction is given by (where, K = rate constant. )

A. 1.5 K

B. 2.5 K

C. $$\frac{{0.693}}{{\text{K}}}$$

D. 6.93 K

Catalyst is a substance, which __________ chemical reaction.

A. Increases the speed of a

B. Decreases the speed of a

C. Can either increase or decrease the speed of a

D. Alters the value of equilibrium constant in a reversible

A chemical reaction is of zero order, when the reaction rate is (where, CA = concentration of reactant)

A. $$ \propto {\text{CA}}$$

B. $$ \propto \frac{1}{{{\text{CA}}}}$$

C. Independent of temperature

D. None of these