CBSE
Multiple Choice QuestionsThe increase in rate constant of a chemical reaction with increasing temperature is (are) due to the fact(s) that
the number of collisions among the reactant molecules increases with increasing temperature
the activation energy of the reaction decreases with increasing temperature
the concentration of the reactant molecules increases with increasing temperature
the number of reactant molecules acquiring the activation energy increases with increasing temperature
What is the activation energy for a reaction if its rate doubles when the temperature is raised from 20°C to 35C ? (R = 8.314 J mol-1 K-1).
342 kJ mol-1
269 kJ mol-1
34.7 kJ mol-1
15.1 kJ mol-1
The rate constant k, for the reaction
is 2.3 x 10-2s-1. Which equation given below describes the change of [N2O5] with time? [N2O5]0 and [N2O5]t correspond to concentration of N2O5 initially and at time t.
[N2O5]t =[N2O5]0 +kt
[N2O5]t = [N2O5]0ekt
log[N2O5]t = log[N2O5]0 +kt
Identify the correct statement from the following in a chemical reaction.
The entropy always increases
The change in entropy along with the suitable change in enthalpy decides the rate of reaction
The enthalpy always decreases
Both the enthalpy and the entropy remain constant
For the reaction :
H2 + Cl2 2HCl , the order of reaction is :
0
2
1
3
The rate of a certain reaction is given by, rate = k [H+]n. The rate increases 100 times when the pH changes from 3 to 1. The order (n) of the reaction is
2
0
1
1.5
Which one of the following is wrong about molecularity of a reaction?
It may be whole number or fractional
It is calculated from reaction mechanism
It is the number of molecules of the reactants taking part in a single step chemical reaction
It is always equal to the order of elementary reaction
A reaction having equal energies of activation for forward and reverse reactions has
S = 0
G = 0
H = 0
H = G = S = 0
For a reaction; A + B product, it was found that rate of reaction increases four times if concentration of 'A' is doubled, but the rate of reaction remains unaffected if concentration of 'B' is doubled. Hence, the rate law for reaction is :
rate = k[A][B]
rate = k[A]2
rate = k [A]2[B]1
rate = k [A]2[B]2
For the reaction A + 2B → C, the reaction rate is doubled, if the concentration of A is doubled. The rate is increased by four times when concentrations of both A and B are increased by four times. The order of the reaction is
3
0
1
2
