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GS Paper IUPSC Prelims 2002
Health & Medicine
Question No. 326Interactive Test Mode
00:00
+2-0.66

Q326. Match List-I (Oxidation number) with List II (The element) and select the correct answer using the codes given below the lists: | List-I (Oxidation number) | List-II (The elements) | | :--- | :--- | | A. 2 | 1. Oxidation number of Mn in $\text{MnO}_2$ | | B. 3 | 2. Oxidation number of S in $\text{H}_2\text{S}_2\text{O}_7$ | | C. 4 | 3. Oxidation number of Ca in $\text{CaO}$ | | D. 6 | 4. Oxidation number of Al in $\text{NaAlH}_4$ | Codes:

Match List-I (Oxidation number) with List II (The element) and select the correct answer using the codes given below the lists:

List-I (Oxidation number)List-II (The elements)
A. 21. Oxidation number of Mn in $\text{MnO}_2$
B. 32. Oxidation number of S in $\text{H}_2\text{S}_2\text{O}_7$
C. 43. Oxidation number of Ca in $\text{CaO}$
D. 64. Oxidation number of Al in $\text{NaAlH}_4$

Codes:

Select the correct option below (or cross out options to eliminate)
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Official Answer Key & Detailed Solution

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Official UPSC Answer KeyUPSC Prelims 2002 • Science and Technology

Correct Answer: Option (A) — A-3; B-4; C-1; D-2

Concept & Option Breakdown

Standard Reference Verified
  • In $\text{CaO}$, oxygen is -2, so Ca is +2 (A matches 3).
  • In $\text{NaAlH}_4$, Na is +1 and H is -1 (hydride), so $\text{Al} = +3$ (B matches 4).
  • In $\text{MnO}_2$, oxygen is -2, so $\text{Mn} = +4$ (C matches 1).
  • In $\text{H}_2\text{S}_2\text{O}_7$, $\text{H} = +1$, $\text{O} = -2$, giving $2(+1) + 2x + 7(-2) = 0 \implies 2x = 12 \implies x = +6$ (D matches 2). Hence, the correct match is A-3, B-4, C-1, D-2.
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Question Specifications & Syllabus Mapping

Examination & YearUPSC Civil Services Preliminary Examination 2002 (Q326)
Paper & Marking SchemeGS Paper I • 2 Marks (-0.66 Negative for incorrect response)
Syllabus Subject & TopicScience and Technology → Health & Medicine
Official Answer KeyOption (A) — A-3; B-4; C-1; D-2

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Frequently Asked Questions — UPSC Prelims 2002 Q326

What is the official answer for UPSC Prelims 2002 GS Paper I Question 326 (Science and Technology)?

The official UPSC answer key for this 2002 Science and Technology (Health & Medicine) question is Option (A): "A-3; B-4; C-1; D-2". Correct attempts carry 2 Marks with -0.66 Negative penalty for wrong answers.

Which UPSC Prelims syllabus topic does this 2002 question belong to?

This question belongs to GS Paper I under the subject "Science and Technology" and micro-topic "Health & Medicine". You can explore all repeated questions from Health & Medicine in Acme AI's 3D Prelims PYQ Realm or practice 50 full-length and sectional tests in the APT Prelims Test Series.

How can I solve this Health & Medicine UPSC Prelims question using option elimination?

To solve Health & Medicine questions in UPSC Prelims, identify extreme modifiers, verify core NCERT conceptual definitions, and eliminate mutually contradictory statement pairs before locking your final option.

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