Category: Chemical Reaction

Pick out the correct statement ?

A. A chemical reaction accompanied by absorption of heat is called an exothermic reaction
B. A chemical reaction accompanied by evolution of heat is called an endothermic reaction
C. The rate constant for a first order reaction does not change on changing the concentration units
D. Chemical equilibrium state is dynamic in nature

Pick out the wrong statement ?

A. In a multistep reaction, the slowest step is the rate determining step
B. In general, the rate of a reaction becomes triple for every 10°C rise in temperature
C. Slow chemical reactions have generally high values of activation energy
D. Molecularity of a reaction cannot be zero but the order of a reaction can be zero

A spherical porous catalyst particle of radius R is subjected to reactant A which reacts to form B by a zero order surface reaction A → B. Film mass transfer resistance is negligible and pore diffusion of A is rate controlling. The effectiveness factor of the catalyst is reported as 7/8. Which of the following statement is true?

A. Inner catalyst core of radius R/8 does not participate in reaction
B. Inner catalyst core of radius R/2 does not participate in reaction
C. Inner catalyst core of radius 7R/8 does not participate in reaction
D. Effectiveness factor for a zero order reaction cannot be 7/8 as it must always be 1