Q. No.Given below two statements:
| Assertion (A): | The oxidation state of Cr in CrO5 is +6. |
| Reason (R): | All oxygen atoms have -2 oxidation number. |
| 1. | Both (A) and (R) are True and (R) correctly explains (A). |
| 2. | Both (A) and (R) are True but (R) does not correctly explain (A). |
| 3. | (A) is True but (R) is False. |
| 4. | Both (A) and (R) are False. |
Subtopic: Introduction to Redox and Oxidation Number |
75%
Level 2: 60%+
Hints
Given below are two statements:
| Assertion (A): | HClO4 is a stronger acid than HClO3. |
| Reason (R): | The oxidation state of Cl in HClO4 is +8 and in HClO3 is +5. |
| 1. | Both (A) and (R) are True, and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True, and (R) is not the correct explanation of (A). |
| 3. | (A) is True, but (R) is False. |
| 4. | Both (A) and (R) are False. |
Subtopic: Introduction to Redox and Oxidation Number |
78%
Level 2: 60%+
Hints
Given below are two statements:
| Statement I: | In some cases, oxygen shows a positive oxidation number, though it is an electronegative element. |
| Statement II: | Fluorine is more electronegative than oxygen. |
| 1. | Statement I is false but Statement II is true. |
| 2. | Both Statement I and Statement II are true. |
| 3. | Both Statement I and Statement II are false. |
| 4. | Statement I is true but Statement II is false. |
Subtopic: Introduction to Redox and Oxidation Number |
78%
Level 2: 60%+
Hints
Assertion: Fluorine exists only in -1 oxidation state.
Reason: Fluorine has 2s22p5 configuration.
1. Both statements are TRUE and Reason is the correct explanation of Assertion.
2. Both statements are TRUE but Reason is NOT the correct explanation of Assertion.
3. Assertion is TRUE and Reason is FALSE.
4. Assertion is FALSE and Reason is TRUE.
Reason: Fluorine has 2s22p5 configuration.
1. Both statements are TRUE and Reason is the correct explanation of Assertion.
2. Both statements are TRUE but Reason is NOT the correct explanation of Assertion.
3. Assertion is TRUE and Reason is FALSE.
4. Assertion is FALSE and Reason is TRUE.
Subtopic: Introduction to Redox and Oxidation Number |
53%
Level 3: 35%-60%
Hints
Assertion: In CrO5, the oxidation number of Cr is +6.
Reason: CrO5 has a butterfly structure in which peroxide bonds are present.
Reason: CrO5 has a butterfly structure in which peroxide bonds are present.
| 1. | Both statements are TRUE and Reason is the correct explanation of Assertion. |
| 2. | Both statements are TRUE but Reason is NOT the correct explanation of Assertion. |
| 3. | Assertion is TRUE and Reason is FALSE. |
| 4. | Assertion is FALSE and Reason is TRUE. |
Subtopic: Introduction to Redox and Oxidation Number |
80%
Level 1: 80%+
Hints
Assertion: The oxidation number of S in H2S2O8 is 6.
Reason: Maximum oxidation state of S is 6 because the maximum oxidation number of an element is equal to the number of valence electrons.
1. Both statements are TRUE and Reason is the correct explanation of Assertion.
2. Both statements are TRUE but Reason is NOT the correct explanation of Assertion.
3. Assertion is TRUE and Reason is FALSE.
4. Assertion is FALSE and Reason is TRUE.
Reason: Maximum oxidation state of S is 6 because the maximum oxidation number of an element is equal to the number of valence electrons.
1. Both statements are TRUE and Reason is the correct explanation of Assertion.
2. Both statements are TRUE but Reason is NOT the correct explanation of Assertion.
3. Assertion is TRUE and Reason is FALSE.
4. Assertion is FALSE and Reason is TRUE.
Subtopic: Introduction to Redox and Oxidation Number |
71%
Level 2: 60%+
Hints
Given below are two statements:
| Assertion (A): | In the presentation \( \mathrm{E}_{\mathrm{Fe}^{3+}}^{\ominus} /_{ \mathrm{Fe}^{2+}}\) \( \text { and } \mathrm{E}_{\mathrm{Cu}^{2+}}^{\ominus} / _{\mathrm{Cu}^{\prime}} \mathrm{Fe}^{3+} / \mathrm{Fe}^{2+} \) and\(\text { } \mathrm{Cu}^{2+} / \mathrm{Cu}\) are redox couples. |
| Reason (R): | A redox couple is the combination of the oxidised and reduced forms of a substance involved in an oxidation or reduction half cell. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | (A) is False but (R) is True. |
Subtopic: Introduction to Redox and Oxidation Number |
74%
Level 2: 60%+
Hints
Which of the following statements are not true about the following decomposition reaction?
| a. | Potassium is undergoing oxidation |
| b. | Chlorine is undergoing oxidation |
| c. | Oxygen is reduced |
| d. | None of the species are undergoing either oxidation or reduction |
The correct choice from the above is:
1. a, b and d
2. b, c and d
3. b, d and a
4. None of the above
Subtopic: Introduction to Redox and Oxidation Number | Oxidizing & Reducing Agents |
68%
Level 2: 60%+
Hints
Match the compounds in column I with the oxidation states of Cl in column II.
Options:
| Column I(Compound) | Column II(Oxidation state) |
| a. Cl2O7 | i. +4 |
| b. NaClO3 | ii. +1 |
| c. Cl2O | iii. +5 |
| d. ClO2 | iv. +7 |
| a | b | c | d | |
| 1. | iii | iv | ii | i |
| 2. | ii | iii | iv | i |
| 3. | iv | iii | ii | i |
| 4. | iv | i | iii | ii |
Subtopic: Introduction to Redox and Oxidation Number |
90%
Level 1: 80%+
Hints
Match the items in column I with column II.
(O.S = oxidation state)
1. a=i; b=ii; c=iii
2. a=ii; b=iii; c=i
3. a=iii; b=ii; c=i
4. a=ii; b=i; c=iii
(O.S = oxidation state)
| Column I | Column II |
| a. Fe O.S in Fe2O3 | i. +2 |
| b. Mn O.S in MnO2 | ii. +3 |
| c. Mn O.S in MnO | iii. +4 |
1. a=i; b=ii; c=iii
2. a=ii; b=iii; c=i
3. a=iii; b=ii; c=i
4. a=ii; b=i; c=iii
Subtopic: Introduction to Redox and Oxidation Number |
91%
Level 1: 80%+
Hints
© 2026 GoodEd Technologies Pvt. Ltd.