Question

A chemical reaction occurs as a result of collisions between reacting molecules. Therefore, the reaction rate is given by:

• A. total number of collision occuring in a unit volume per second
• B. fraction of molecules which possess energy less than the threshold energy
• C. total number of effective collisions
• D. none of the above

Answer 1

Answer: (A), (C)

total number of effective collisions
total number of collision occuring in a unit volume per second

According to collision theory, the reaction occurs when molecules collide with each other. The rate is given by:

Rate=$Z_{AB}\times f$

Where $Z_{AB}$=collision frequency of reactants $A$ & $B$.

i.e. total number of collisions occurring in a unit volume per second. &

$f$=fraction of effective collisions.

So, the rate depends on both (A) & (C)