## Chemistry MCQ on Law of Mass Action for NEET, JEE, Medical and Engineering Exam 2021

MCQ on Law of Mass Action: Chemistry is considered to be the most scoring subject in NEET JEE Exam. As it is one of the easiest scoring subjects, it is often ignored and undermined a subject. But if you want to get an edge over others, here is a tip, master NEET/JEE Chemistry concepts. Chemistry demands the attention of students in understanding reactions and concrete basic understanding but once done it only gets easier from there. Mastering NCERT syllabus for NEET/JEE Chemistry should be topping your list of to-do for chemistry.

In this post we are providing you MCQ on Law of Mass Action, which will be beneficial for you in upcoming NEET, JEE, Medical and Engineering Exams.

## MCQ on Law of Mass Action

Q1. Half-life of 10g of radioactive substance is 10 days. The half-life of 20 g is _______.
a) 5 days
b) 10 days
c) 15 days
d) 20 days

b) 10 days

Q2. For a reaction A → Products the rate of reaction doubles when the concentration of A is increased by 4 times. The order of the reaction is _______.
a) 1/2
b) 1
c) 2
d) 4

a) 1/2

Q3. K for a zero-order reaction is 2 x 10-2 mole/L/sec. If the concentration of reactant after 25 sec is 0.5M, the initial concentration must have been _______.
a) 0.5M
b) 0.75M
c) 1.0M
d) 1.25M

c) 1.0M

Q4. What is the half-life of a radioactive substance if 87.5% of any given amount of the substance disintegrate in 40 minutes?
a) 13 min 20 sec
b) 15 min 20 sec
c) 13 min 40 sec
d) 15 min 40 sec

a) 13 min 20 sec

Q5. Which of the following is not correct?
a) The rate law is an experimental fact, but the law of mass action is theoretical
b) The rate law is always different from the expression of the law of mass action
c) The rate law is more informative than the law of mass action for the development of a mechanism
d) The order of a reaction is equal to the sum of the powers of the concentration terms in the rate law

b) The rate law is always different from the expression of the law of mass action

Q6. The chemical reactions in which reactants need a high amount of activation energy are generally _______.
a) fast
b) slow
c) very fast
d) instantaneous

b) slow

Q7. If a reaction with t1/2 = 69.3 sec, has a rate constant 10-2 per sec the order is _______.
a) 1
b) 2
c) 3
d) 4

a) 1

Q8. The number of atoms or molecules whose concentration alters during a chemical change is its _______.
a) molecularity
b) order of reaction
c) change in reaction
d) None of the above

b) order of reaction

Q9. The temperature coefficient of a reaction is 2. How many times the rate of reaction increases when the temperature is increased from 30oC to 60oC.
a) 4 times
b) 8 times
c) 12 times
d) 16 times

b) 8 times

Q10. A first-order reaction is 75% complete after 32 minutes. When was 50% of the reaction completed?
a) 4 min
b) 8 min
c) 12 min
d) 16 min

d) 16 min