General Principles of Isolation of Elements Practice Questions
Class 12 · Chemistry · 2721 free MCQs with instant results and detailed explanations.
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Easy
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Medium
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Hard
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Topics in General Principles of Isolation of Elements
Thermodynamic Principles
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Electrochemical Principles
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Refining Methods
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Sample Questions from General Principles of Isolation of Elements
Here are 10 sample questions. Start a quiz to get randomized questions with scoring.
Q1
Easy
Which of the following statements is true regarding Gibbs free energy?
A.
Gibbs free energy decreases for spontaneous processes.
B.
Gibbs free energy increases for spontaneous processes.
C.
Gibbs free energy is independent of temperature.
D.
Gibbs free energy is always a positive value.
Show Answer & Explanation
Correct Answer: A
Gibbs free energy decreases for spontaneous processes, indicating that the process can occur without external work.
Q2
Easy
For a reaction at equilibrium, what is the value of ΔG?
A.
ΔG > 0
B.
ΔG < 0
C.
ΔG = 0
D.
ΔG cannot be determined
Show Answer & Explanation
Correct Answer: C
At equilibrium, the change in Gibbs free energy (ΔG) is zero, indicating no net change in the system.
Q3
Easy
Which of the following processes is endothermic?
A.
Dissolving ammonium nitrate in water
B.
Combustion of gasoline
C.
Formation of water from hydrogen and oxygen
D.
Metal oxidation
Show Answer & Explanation
Correct Answer: A
Dissolving ammonium nitrate in water absorbs heat, making it an endothermic process.
Q4
Medium
Which of the following processes increases the entropy of a system?
A.
Freezing of water
B.
Condensation of steam
C.
Melting of ice
D.
Sublimation of dry ice
Show Answer & Explanation
Correct Answer: C
Melting increases disorder (entropy) as solid ice turns to liquid water.
Q5
Medium
What is the Gibbs free energy change at equilibrium?
A.
0
B.
Positive
C.
Negative
D.
Cannot be determined
Show Answer & Explanation
Correct Answer: A
At equilibrium, the Gibbs free energy change is zero, indicating no net change in the system.
Q6
Medium
Which statement about Hess's Law is true?
A.
It applies only to gases
B.
It is concerned with enthalpy changes
C.
It can only be applied at constant temperature
D.
It only applies to exothermic reactions
Show Answer & Explanation
Correct Answer: B
Hess's Law states that the total enthalpy change is the sum of the enthalpy changes for individual steps, regardless of the path taken.
Q7
Medium
For a reaction with a high activation energy, what is expected at lower temperatures?
A.
Increased reaction rate
B.
Decreased reaction rate
C.
No change in reaction rate
D.
Reaction goes to completion
Show Answer & Explanation
Correct Answer: B
Higher activation energy leads to fewer molecules having sufficient energy to react at lower temperatures, decreasing the rate.
Q8
Hard
Which of the following statements about the Gibbs free energy is incorrect?
A.
A negative change in Gibbs free energy indicates a spontaneous process.
B.
Gibbs free energy is temperature dependent.
C.
A positive change in Gibbs free energy indicates a spontaneous process.
D.
At equilibrium, the change in Gibbs free energy is zero.
Show Answer & Explanation
Correct Answer: C
A positive change in Gibbs free energy indicates the process is non-spontaneous, not spontaneous.
Q9
Hard
Which of the following processes is NOT an endothermic reaction?
A.
Sublimation of dry ice
B.
Dissolving ammonium nitrate in water
C.
Decomposition of calcium carbonate
D.
Combustion of methane
Show Answer & Explanation
Correct Answer: D
Combustion of methane is an exothermic process, releasing energy.
Q10
Hard
What is the effect of increasing temperature on the equilibrium constant (K) of an exothermic reaction?
A.
K increases
B.
K decreases
C.
K remains constant
D.
K becomes zero
Show Answer & Explanation
Correct Answer: B
According to Le Chatelier's principle, increasing temperature favors the endothermic direction, thus decreasing K for exothermic reactions.
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General Principles of Isolation of Elements — Class 12 Chemistry Practice Questions Online
This page contains 2721 practice MCQs for the chapter General Principles of Isolation of Elements in Class 12 Chemistry. The questions are organized by difficulty — 855 easy, 1340 medium, 526 hard — so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit. This chapter covers 3 topics, giving you comprehensive coverage of the entire chapter.