MCQs Related to IMPORTANCE OF EQUILIBRIUM CONSTANT || 10TH CHEMISTRY
1. What does the equilibrium constant help to predict?
A) Temperature of a reaction
B) Direction and extent of a reaction
C) Pressure changes in a reaction
D) Volume of the reactants
2. When Qc < Kc, what happens to the reaction?
A) It goes in reverse direction
B) It stops
C) It goes in forward direction
D) It remains at equilibrium
3. What is the reaction quotient (Qc)?
A) The ratio of products to reactants at equilibrium
B) The concentration of reactants at equilibrium
C) The value obtained using concentrations at any moment
D) The temperature of the reaction
4. If Qc > Kc, what does this indicate?
A) The reaction is at equilibrium
B) The reaction goes in reverse direction
C) The reaction goes in forward direction
D) The products are favored
5. A large numerical value of Kc indicates what about the reaction?
A) Almost all reactants are present
B) The reaction goes to completion
C) The reaction is at equilibrium
D) The reaction is reversible
6. What is a characteristic of reactions with a small Kc value?
A) Products are favored
B) Reactants are favored
C) Equal amounts of reactants and products
D) The reaction goes to completion
7. Why do reversible reactions not go to completion?
A) They require more time
B) They have equal rates of forward and reverse reactions
C) They are not affected by temperature
D) They always favor reactants
8. What happens when Qc = Kc?
A) The reaction goes in forward direction
B) The reaction goes in reverse direction
C) The reaction has reached equilibrium
D) The reaction stops
9. What are the major components of the atmosphere?
A) Carbon dioxide and nitrogen
B) Nitrogen and oxygen
C) Oxygen and argon
D) Helium and hydrogen
10. What is nitrogen used to manufacture?
A) Sulphuric acid
B) Ammonia
C) Carbon dioxide
D) Water
11. Which chemical is produced from ammonia?
A) Nitric acid
B) Nitrogenous fertilizers
C) Sulphur dioxide
D) Methane
12. What is oxygen used to produce?
A) Nitrogen
B) Water
C) Sulphur dioxide
D) Ammonia
13. What is sulphur dioxide used for?
A) To produce ammonia
B) To manufacture sulphuric acid
C) To make fertilizers
D) To make water
14. What does a Kc value indicate?
A) The speed of the reaction
B) The extent of the reaction
C) The temperature of the reaction
D) The pressure in the reaction
15. Which of the following reactions typically does not go to completion?
A) Combustion reactions
B) Reversible reactions
C) Oxidation reactions
D) Acid-base reactions
16. If the concentration of products is high, what can we conclude about Kc?
A) Kc is small
B) Kc is large
C) Kc is equal to zero
D) Kc is not relevant
17. At equilibrium, what can be said about the rates of forward and reverse reactions?
A) Forward rate is higher
B) Reverse rate is higher
C) Both rates are equal
D) Both rates are zero
18. In which century did the use of atmospheric gases in chemical manufacturing begin?
A) 19th century
B) 20th century
C) 21st century
D) 18th century
19. What happens if the concentration of reactants is increased?
A) Qc increases
B) Qc decreases
C) Kc changes
D) Reaction stops
20. What is the significance of measuring concentrations at any time?
A) It helps in determining Kc
B) It shows the final products
C) It provides the temperature
D) It stops the reaction
21. How do we determine if a reaction is at equilibrium?
A) By comparing Qc with Kc
B) By measuring temperature
C) By observing color changes
D) By calculating pressure
22. What does a Kc value that is neither small nor large indicate?
A) Only products are present
B) Comparable amounts of reactants and products
C) The reaction is complete
D) Only reactants are present
23. What is the result of a large Kc value for a reaction?
A) Reactants dominate the equilibrium
B) Products dominate the equilibrium
C) No products are formed
D) The reaction is very slow
24. Why is Qc useful in predicting reaction direction?
A) It shows temperature changes
B) It compares concentrations at equilibrium
C) It indicates energy changes
D) It compares the value of Qc with Kc
25. What does it mean if almost all reactants are present at equilibrium?
A) Kc is large
B) Kc is small
C) Kc is infinite
D) Kc is zero
26. Why might a reaction not yield exactly 50% products and 50% reactants at equilibrium?
A) Reactions are too fast
B) Different rates of forward and reverse reactions
C) Temperature is too high
D) All reactants are used
27. What is one application of nitrogen from the atmosphere?
A) Producing hydrogen
B) Making sulfuric acid
C) Creating fertilizers
D) Generating electricity
28. Which reaction characteristic is indicated by a small Kc value?
A) High product concentration
B) High reactant concentration
C) Low temperature
D) Fast reaction rate
29. What does Kc signify in a chemical reaction?
A) The number of reactants
B) The energy change in the reaction
C) The ratio of products to reactants at equilibrium
D) The speed of the reaction
30. Why are gases like nitrogen and oxygen significant in chemistry?
A) They are rare in the atmosphere
B) They are used to make other chemicals
C) They have no chemical applications
D) They are only present in small amounts
Correct Answers:
1.B
2.C
3.C
4.B
5.B
6.B
7.B
8.C
9.B
10.B
11.B
12.C
13.B
14.B
15.B
16.B
17.C
18.B
19.A
20.A
21.A
22.B
23.B
24.D
25.B
26.B
27.C
28.B
29.C
30.B