CBSE
Multiple Choice QuestionsThe half life of a radioactive element is 40 days. Calculate the average life
5.76 days
57.6 days
646 days
4.56 days
A first order reaction, which is 30% complete in 30 minutes has a half-life period of
102.2 min
58.2 min
24.2 min
120.2 min
One of the hazardous explosion is the generation of 90Sr and its subsequent incorporation in bones. This nuclide has a half life of 28.1 years. Suppose one microgram was absorbed by a new born child. How much 90Sr will remain in his bones after 20 years?
0.061 µg
0.080µg
0.050µg
0.030µg
For a reaction, the half-life is independent of initial concentration. What is the order of that reaction?
Zero
One
Two
Three
How will the rate of reaction , 2NO + O2 2NO2 change, if the volume of the reaction vessel is doubled?
It will diminish to 1/4 of the initial value
It will diminish to 1/8 of the initial value
It will grow four times
It will grow eight times
There is a steam of neutrons with a kinetic energy of 0.0327 eV. If the half life of neutrons s 700 s, what fraction of neutrons will decay before they travel a distance of 10 km?
0.001
0.004
0.006
0.009
The chemical reaction, 2O3 3O2 proceeds as follows:
Step 1 : O3 O2 + O ...(fast)
Step 2 : O + O3 2O2 ...(slow)
The rate law expression should be
r = k' [O3][O2]
r = k'[O3]2[O2]-1
r = k'[O3]2
unpredictable
Consider the following statements :
I. Increase in concentration of reactant increases the rate of a zero order reaction
II. Rate constant k is equal to collision frequency A , if Ea =0
III. Rate constant k is equal to collision
frequency A , if Ea = ∞
IV. ln k vs T is a straight line
V. ln k vs 1/T is a straight line
Correct statements are :
I and IV
II and V
III and IV
II and III
The rate of reaction , 2NO + Cl2 2NOCl becomes double when the concentration of Cl2 is doubled. However, when the concentration of both the reactants is doubled the rate becomes eight times. What is order of the reaction?
First
Second
Third
Zero
For a chemical reaction A B, the rate of the reaction is 2x10-3 mol dm-3 s-1 , when the initial concentration is 0.05 mol dm-3 . The rate of the same reaction is 1.6 x 10-2 mol dm-3 s-1 , when the initial concentration is 0.1 mol dm-3 .The order of the reaction is :
2
0
3
1
