Q. In the reaction 2Fe2O3 + 3C → 4Fe + 3CO2, what is being reduced? (2020) 2020
A.
Fe2O3
B.
C
C.
CO2
D.
Fe
Show solution
Solution
Fe2O3 is reduced to Fe, as it gains electrons during the reaction.
Correct Answer:
A
— Fe2O3
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Q. In the reaction 2Fe2O3 + 3C → 4Fe + 3CO2, which element is oxidized?
A.
Iron
B.
Carbon
C.
Oxygen
D.
None
Show solution
Solution
Carbon is oxidized as it loses electrons to form CO2.
Correct Answer:
B
— Carbon
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Q. In the reaction 2Fe2O3 + 3C → 4Fe + 3CO2, which species is oxidized? (2019)
A.
Fe2O3
B.
C
C.
Fe
D.
CO2
Show solution
Solution
In this reaction, carbon (C) is oxidized as it loses electrons to form CO2.
Correct Answer:
B
— C
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Q. In the reaction 2Fe^3+ + 2I^- → 2Fe^2+ + I2, which species is the reducing agent?
A.
Fe^3+
B.
I^-
C.
Fe^2+
D.
I2
Show solution
Solution
I^- donates electrons to Fe^3+, thus it is the reducing agent.
Correct Answer:
B
— I^-
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Q. In the reaction 2Fe²⁺ + 2e⁻ → 2Fe, what is being reduced? (2021)
A.
Fe²⁺
B.
Fe
C.
e⁻
D.
None of the above
Show solution
Solution
In this reaction, Fe²⁺ is being reduced as it gains electrons to form Fe.
Correct Answer:
A
— Fe²⁺
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Q. In the reaction 2Fe²⁺ + 2MnO4⁻ → 2Fe³⁺ + 2Mn²⁺, what is the oxidation state change for iron? (2021)
A.
+2 to +3
B.
+3 to +2
C.
0 to +2
D.
−2 to 0
Show solution
Solution
Iron changes its oxidation state from +2 to +3, indicating that it is oxidized.
Correct Answer:
A
— +2 to +3
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Q. In the reaction 2Fe²⁺ + Cl2 → 2Fe³⁺ + 2Cl⁻, what is being oxidized? (2021)
A.
Fe²⁺
B.
Cl2
C.
Fe³⁺
D.
Cl⁻
Show solution
Solution
In this reaction, Fe²⁺ is being oxidized to Fe³⁺ as it loses electrons.
Correct Answer:
A
— Fe²⁺
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Q. In the reaction 2Fe²⁺ + Cl2 → 2Fe³⁺ + 2Cl⁻, which element is oxidized? (2021)
Show solution
Solution
Iron (Fe) is oxidized from +2 to +3 oxidation state in this reaction.
Correct Answer:
A
— Fe
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Q. In the reaction 2H2 + O2 → 2H2O, how many grams of oxygen are required to completely react with 4 grams of hydrogen?
A.
16 g
B.
8 g
C.
32 g
D.
4 g
Show solution
Solution
4 g of H2 = 2 moles. 1 mole of O2 is needed for 2 moles of H2, so 1 mole of O2 = 32 g is required.
Correct Answer:
B
— 8 g
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Q. In the reaction 2H2 + O2 → 2H2O, how many grams of oxygen are required to react with 4 grams of hydrogen?
A.
16 g
B.
8 g
C.
4 g
D.
2 g
Show solution
Solution
First, calculate moles of H2: 4 g / 2 g/mol = 2 moles. From the reaction, 2 moles of H2 require 1 mole of O2. Therefore, 2 moles of O2 = 32 g.
Correct Answer:
B
— 8 g
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Q. In the reaction 2H2 + O2 → 2H2O, how many grams of water are produced from 4 grams of hydrogen?
A.
18 g
B.
36 g
C.
54 g
D.
72 g
Show solution
Solution
4 grams of H2 is 2 moles (4 g / 2 g/mol). According to the equation, 2 moles of H2 produce 2 moles of H2O, which is 36 g (2 moles x 18 g/mol).
Correct Answer:
B
— 36 g
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Q. In the reaction 2H2 + O2 → 2H2O, how many grams of water can be produced from 4 grams of hydrogen?
A.
36 g
B.
18 g
C.
72 g
D.
9 g
Show solution
Solution
4 g of H2 = 2 moles. 2 moles of H2 produce 2 moles of H2O = 2 * 18 g = 36 g.
Correct Answer:
A
— 36 g
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Q. In the reaction 2H2 + O2 → 2H2O, how many liters of H2O vapor are produced from 4 liters of H2?
A.
4 L
B.
8 L
C.
2 L
D.
6 L
Show solution
Solution
4 L of H2 produces 4 L of H2O vapor at STP.
Correct Answer:
B
— 8 L
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Q. In the reaction 2H2 + O2 → 2H2O, how many liters of water vapor are produced from 4 liters of hydrogen at STP?
A.
4 L
B.
8 L
C.
2 L
D.
6 L
Show solution
Solution
4 L of H2 produces 4 L of H2O since the ratio is 1:1.
Correct Answer:
B
— 8 L
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Q. In the reaction 2H2 + O2 → 2H2O, how many moles of O2 are required to completely react with 6 moles of H2?
A.
2 moles
B.
3 moles
C.
4 moles
D.
6 moles
Show solution
Solution
From the balanced equation, 2 moles of H2 require 1 mole of O2. Therefore, 6 moles of H2 will require (6/2) = 3 moles of O2.
Correct Answer:
B
— 3 moles
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Q. In the reaction 2H2 + O2 → 2H2O, how many moles of O2 are required to react with 6 moles of H2?
A.
3 moles
B.
4 moles
C.
6 moles
D.
2 moles
Show solution
Solution
According to the stoichiometry of the reaction, 2 moles of H2 require 1 mole of O2. Therefore, 6 moles of H2 will require (6/2) = 3 moles of O2.
Correct Answer:
A
— 3 moles
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Q. In the reaction 2H2 + O2 → 2H2O, how many moles of water are produced from 4 moles of hydrogen?
A.
2 moles
B.
4 moles
C.
6 moles
D.
8 moles
Show solution
Solution
According to the stoichiometry of the reaction, 2 moles of H2 produce 2 moles of H2O. Therefore, 4 moles of H2 will produce 4 moles of H2O.
Correct Answer:
B
— 4 moles
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Q. In the reaction 2H2 + O2 → 2H2O, if 3 moles of O2 are available, how many moles of H2 are required?
A.
3 moles
B.
6 moles
C.
1.5 moles
D.
4.5 moles
Show solution
Solution
According to the stoichiometry, 1 mole of O2 requires 2 moles of H2. Therefore, 3 moles of O2 will require 3 x 2 = 6 moles of H2.
Correct Answer:
B
— 6 moles
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Q. In the reaction 2H2 + O2 → 2H2O, if you start with 3 moles of O2, how many moles of H2 are required?
A.
3 moles
B.
6 moles
C.
1.5 moles
D.
4 moles
Show solution
Solution
According to the stoichiometry, 1 mole of O2 requires 2 moles of H2. Therefore, 3 moles of O2 will require 6 moles of H2.
Correct Answer:
B
— 6 moles
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Q. In the reaction 2H2 + O2 → 2H2O, what is the ratio of moles of hydrogen to moles of oxygen?
A.
1:1
B.
2:1
C.
2:2
D.
1:2
Show solution
Solution
The balanced equation shows that 2 moles of H2 react with 1 mole of O2, giving a ratio of 2:1.
Correct Answer:
B
— 2:1
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Q. In the reaction 2H2 + O2 → 2H2O, which element is oxidized?
Show solution
Solution
Oxygen (O) is oxidized as it goes from 0 in O2 to -2 in H2O.
Correct Answer:
B
— O
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Q. In the reaction 2Mg + O2 → 2MgO, which element is oxidized? (2021)
A.
Magnesium
B.
Oxygen
C.
Both Magnesium and Oxygen
D.
Neither Magnesium nor Oxygen
Show solution
Solution
Magnesium is oxidized as it loses electrons and its oxidation state increases from 0 to +2.
Correct Answer:
A
— Magnesium
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Q. In the reaction 2MnO4- + 5C2O4^2- + 16H+ → 2Mn^2+ + 10CO2 + 8H2O, what is being oxidized? (2019)
A.
MnO4-
B.
C2O4^2-
C.
H+
D.
CO2
Show solution
Solution
C2O4^2- (oxalate ion) is being oxidized to CO2 in this reaction.
Correct Answer:
B
— C2O4^2-
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Q. In the reaction 2MnO4^- + 5C2O4^2- + 6H+ → 2Mn^2+ + 10CO2 + 3H2O, what is the role of MnO4^-? (2023)
A.
Oxidizing agent
B.
Reducing agent
C.
Neutral agent
D.
Catalyst
Show solution
Solution
MnO4^- acts as an oxidizing agent as it gains electrons and is reduced to Mn^2+.
Correct Answer:
A
— Oxidizing agent
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Q. In the reaction 2MnO4⁻ + 5C2O4²⁻ + 16H⁺ → 2Mn²⁺ + 10CO2 + 8H2O, which species is reduced? (2019)
A.
MnO4⁻
B.
C2O4²⁻
C.
H⁺
D.
CO2
Show solution
Solution
In this reaction, MnO4⁻ is reduced to Mn²⁺ as it gains electrons.
Correct Answer:
A
— MnO4⁻
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Q. In the reaction 2Na + Cl2 → 2NaCl, how many grams of NaCl can be produced from 2 moles of Na? (2021)
A.
58.5 g
B.
117 g
C.
29.25 g
D.
146 g
Show solution
Solution
2 moles of Na produce 2 moles of NaCl. Molar mass of NaCl = 58.5 g/mol. Therefore, 2 moles of NaCl = 2 × 58.5 g = 117 g.
Correct Answer:
B
— 117 g
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Q. In the reaction 2Na + Cl2 → 2NaCl, how many grams of NaCl can be produced from 5 g of Na?
A.
10 g
B.
15 g
C.
20 g
D.
25 g
Show solution
Solution
5 g of Na = 0.217 moles. 2 moles of Na produce 2 moles of NaCl, so 0.217 moles of NaCl = 0.217 * 58.5 g = 12.7 g.
Correct Answer:
A
— 10 g
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Q. In the reaction 2Na + Cl2 → 2NaCl, how many grams of sodium chloride are produced from 4 moles of sodium? (2023)
A.
236 g
B.
118 g
C.
472 g
D.
59 g
Show solution
Solution
4 moles of Na produce 4 moles of NaCl. Molar mass of NaCl = 58.5 g/mol. Therefore, 4 × 58.5 = 236 g.
Correct Answer:
A
— 236 g
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Q. In the reaction 2Na + Cl2 → 2NaCl, how many moles of NaCl are produced from 4 moles of Na? (2023)
A.
2 moles
B.
4 moles
C.
6 moles
D.
8 moles
Show solution
Solution
From 2 moles of Na, 2 moles of NaCl are produced. Therefore, from 4 moles of Na, 4 moles of NaCl are produced.
Correct Answer:
B
— 4 moles
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Q. In the reaction 2SO2(g) + O2(g) ⇌ 2SO3(g), what happens if SO2 is removed from the system?
A.
Shift to the right
B.
Shift to the left
C.
No change
D.
Increase in temperature
Show solution
Solution
Removing SO2 will shift the equilibrium to the left to produce more SO2, according to Le Chatelier's principle.
Correct Answer:
B
— Shift to the left
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Major Competitive Exams MCQ & Objective Questions
Major Competitive Exams play a crucial role in shaping the academic and professional futures of students in India. These exams not only assess knowledge but also test problem-solving skills and time management. Practicing MCQs and objective questions is essential for scoring better, as they help in familiarizing students with the exam format and identifying important questions that frequently appear in tests.
What You Will Practise Here
Key concepts and theories related to major subjects
Important formulas and their applications
Definitions of critical terms and terminologies
Diagrams and illustrations to enhance understanding
Practice questions that mirror actual exam patterns
Strategies for solving objective questions efficiently
Time management techniques for competitive exams
Exam Relevance
The topics covered under Major Competitive Exams are integral to various examinations such as CBSE, State Boards, NEET, and JEE. Students can expect to encounter a mix of conceptual and application-based questions that require a solid understanding of the subjects. Common question patterns include multiple-choice questions that test both knowledge and analytical skills, making it essential to be well-prepared with practice MCQs.
Common Mistakes Students Make
Rushing through questions without reading them carefully
Overlooking the negative marking scheme in MCQs
Confusing similar concepts or terms
Neglecting to review previous years’ question papers
Failing to manage time effectively during the exam
FAQs
Question: How can I improve my performance in Major Competitive Exams?Answer: Regular practice of MCQs and understanding key concepts will significantly enhance your performance.
Question: What types of questions should I focus on for these exams?Answer: Concentrate on important Major Competitive Exams questions that frequently appear in past papers and mock tests.
Question: Are there specific strategies for tackling objective questions?Answer: Yes, practicing under timed conditions and reviewing mistakes can help develop effective strategies.
Start your journey towards success by solving practice MCQs today! Test your understanding and build confidence for your upcoming exams. Remember, consistent practice is the key to mastering Major Competitive Exams!
