Chemical Equilibrium Test 01

Total Questions: 27

1 - The characteristics of reversible reactions are the following except:

A ) Products never recombine to form reactants ✅
B ) They never complete
C ) They proceed in both ways
D ) They have a double arrow between reactants and products

2 - When a system is at equilibrium state:

A ) The concentration of reactants and products becomes equal
B ) The opposing reactions ( forward and reverse) stop
C ) The rate of the reverse reaction becomes very low
D ) The rates of the forward and reverse reactions become equal ✅

3 - When the magnitude of Kc is very large it indicates:

A ) reaction mixture consists of almost all products ✅
B ) reaction mixture has almost all reactants
C ) reaction has not gone to completion
D ) reaction mixture has negligible products

4 - When the magnitude of Kc is very small it indicates:

A ) equilibrium will never establish
B ) all reactants will be converted into products
C ) reaction will go to the completion
D ) The amount of products is negligible ✅

5 - Reactions which have comparable amounts of reactants and products at equilibrium state have:

A ) Very small Kc value
B ) Very large Kc value
C ) moderate Kc value ✅
D ) None of the above

6 - At dynamic equilibrium:

A ) The reaction stops to proceed
B ) The amounts of reactants and products are equal
C ) The speeds of the forward and reverse reactions are equal ✅
D ) The reaction can no longer be reversed

7 - In an irreversible reaction dynamic equilibrium:

A ) never establishes ✅
B ) establishes before the completion of reaction
C ) establishes after the completion of reaction
D ) establishes rapidly

8 - A reverse reaction is one that:

A ) Proceeds from left to right
B ) in which reactants react to form products
C ) slows down gradually
D ) speeds up gradually ✅

9 - For the reaction between PCl3 and Cl2 to form PCI5, the units of Kc are:

A ) mol dm-³
B ) mol-¹ dm-³
C ) mol-¹ dm³ ✅
D ) mol dm³

10 - The reactions in which the products do not recombine to form reactants are called:

A ) irreversible reactions ✅
B ) reversible reactions
C ) decomposition reactions
D ) addition reactions

11 - Which one of the following statements is not correct about active mass?

A ) rate of reaction is directly proportional to active mass
B ) active mass is taken in molar concentration
C ) active mass is represented by square brackets
D ) active mass means total mass of substances ✅

12 - The reactions in which the products can recombine to form reactants are called:

A ) irreversible reactions
B ) reversible reactions ✅
C ) decomposition reactions
D ) additional reactions

13 - The colour of iodine is:

A ) purple ✅
B ) black
C ) red
D ) pink

14 - The colour of hydrogen iodide is:

A ) colourless ✅
B ) black
C ) red
D ) pink

16 - When a reaction ceases to proceed, it is called:

A ) chemical equilibrium state
B ) static equilibrium state ✅
C ) dynamic equilibrium state
D ) all of the above

17 - Goldberg and Waage put forward law of mass action in:

A ) 1860
B ) 1869 ✅
C ) 1870
D ) 1879

19 - Which gas is used to prepare ammonia?

A ) N2 ✅
B ) O2
C ) Cl2
D ) S

21 - Equilibrium constant has no unit when number of moles of reactants and products are:

A ) Completion ✅
B ) equilibrium state
C ) backward
D ) none of the above

22 - The two major components of Atmosphere are:

A ) carbon and nitrogen
B ) nitrogen and oxygen ✅
C ) oxygen and chlorine
D ) none of the above

23 - Which type of reactions do not go to completion?

A ) irreversible reactions
B ) reversible reactions ✅
C ) addition reactions
D ) decomposition reactions

24 - Which type of reactions speed up gradually?

A ) irreversible reactions
B ) reverse reactions ✅
C ) forward reactions
D ) decomposition reactions

25 - Such reactions which continue in both directions are called:

A ) Irreversible
B ) Reversible ✅
C ) Non-creative
D ) Dynamic

26 - In a chemical reaction, the substances that combine are called:

A ) reactants ✅
B ) products
C ) masses
D ) materials

27 - 'Kc' represents:

A ) iconic product of water
B ) equilibrium constant ✅
C ) reaction quotient
D ) proportionality constant