Q.80 Chemistry ⭐ 360° Option Elimination Active

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NEET 2023 Chemistry Question 80 Solution

Topic: The s-Block Elements · Official NTA Booklet Code G5

Question

Which one of the following statements is correct?

(1)Mg plays roles in neuromuscular function and interneuronal transmission.
(2)The daily requirement of Mg and Ca in the human body is estimated to be 0.2 -0.3 g.
(3)All enzymes that utilise ATP in phosphate transfer require Ca as the cofactor.
(4)The bone in human body is an inert and unchanging substance.

✓

Verified Against NTA Final Answer Key

Option (2) : The daily requirement of Mg and Ca in the human body is estimated to be 0.2 - 0.3 g.

📚 The s-Block Elements Medium

📋 Given Parameters & Problem Setup

Subject Biological roles of Group 2 metals (Mg and Ca)

Candidate statements 4 biological statements evaluated for factual correctness

⚡

The 30-Second Exam Hall Shortcut: ⚡ NCERT Biological Milestone: Daily Human Requirement is 200–300 mg (0.2–0.3 g)

⏱️ Save ~30 seconds

NCERT s-block verbatim: "The daily requirement in the human body has been estimated to be 200–300 mg (0.2–0.3 g)." Neuromuscular signaling is controlled by Ca²⁺ (not Mg²⁺); ATP kinase enzymes require Mg²⁺ (not Ca²⁺); bone is dynamically remodeling (never inert). Statement (2) is verified in 10 seconds!

1 Check Statement (1): Neuromuscular function & neurotransmitter release are mediated by Ca²⁺, not Mg²⁺ (False).

2 Check Statement (2): Daily requirement of Mg and Ca is 200–300 mg = 0.2–0.3 g (Verbatim NCERT, True).

3 Check Statement (3): ATP phosphate transfer enzymes require Mg²⁺ cofactor, not Ca²⁺ (False).

4 Check Statement (4): Bone is dynamic living tissue, not inert (False).

5 Lock Option (2) with 100% confidence.

🛡️

Why You Can 100% Trust This Shortcut: Exact canonical statement from NCERT Chemistry Textbook on Group 2 Elements.

📐

Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Evaluate Statement (2): Daily Dietary Requirements

According to NCERT s-Block Elements (Biological Importance of Magnesium and Calcium): "The daily requirement in the human body has been estimated to be 200 – 300 mg (0.2 – 0.3 g)."

\text{Daily adult requirement of Mg and Ca} = 200 - 300\text{ mg} = 0.2 - 0.3\text{ g} \quad (\text{Correct})

Step 2

Evaluate Statement (1): Neuromuscular Signaling

Calcium ions (Ca²⁺) play critical roles in neuromuscular function, interneuronal transmission, cell membrane integrity, and blood coagulation. Magnesium (Mg²⁺) is not the primary ion for interneuronal transmission:

\text{Neuromuscular transmission} \iff \text{Regulated by } \text{Ca}^{2+} \; (\text{not } \text{Mg}^{2+})

Step 3

Evaluate Statement (3): ATP Enzymatic Phosphate Transfer

All enzymes that utilize ATP in phosphate transfer require magnesium (Mg²⁺) as the cofactor, forming an essential [Mg-ATP]²⁻ complex. Calcium is not the cofactor for these kinases:

\text{ATP-utilizing enzymes} \iff \text{Require } \text{Mg}^{2+} \text{ as cofactor} \; (\text{not } \text{Ca}^{2+})

Step 4

Evaluate Statement (4): Biological Nature of Bone

Bone is not an inert and unchanging substance; it is constantly being dissolved, redeposited, and dynamically remodeled through osteoblast and osteoclast activity:

\text{Bone dynamic equilibrium: } \text{Ca}_{10}(\text{PO}_4)_6(\text{OH})_2 \rightleftharpoons \text{Circulating } \text{Ca}^{2+} + \text{PO}_4^{3-}

⭐

360° Option Elimination Engine Key Feature

Diagnose every choice: Know exactly why the right option works and why distractors fail.

4-Option Deep Scan

1 (1)

✗ Incorrect

Verdict & Scientific Reason:

Interneuronal transmission and neuromuscular junctions are mediated by calcium ions (Ca²⁺), not magnesium.

⚠️

Student Fallacy (Why candidates pick this trap): Candidate interchanged the distinct physiological roles of magnesium and calcium.

2 (2)

✓ 100% Correct

Verdict & Scientific Reason:

Accurate: NCERT explicitly states the daily adult human requirement of both Mg and Ca is 200–300 mg (0.2–0.3 g).

💡

Why this is airtight: None. Candidate recalled the precise nutritional biochemistry values from NCERT.

3 (3)

✗ Incorrect

Verdict & Scientific Reason:

Magnesium (Mg²⁺) is the mandatory cofactor for ATP-utilizing enzymes (kinases), not calcium.

⚠️

Student Fallacy (Why candidates pick this trap): Candidate swapped Mg²⁺ cofactor requirement with Ca²⁺.

4 (4)

✗ Incorrect

Verdict & Scientific Reason:

Bone is living, dynamic tissue constantly undergoing resorption and remodeling.

⚠️

Student Fallacy (Why candidates pick this trap): Candidate mistook mineralized structural hydroxyapatite for non-living inert matter.

⚠️

NTA Trap Alert: Swapping Ca²⁺ and Mg²⁺ Functions

NTA deliberately tests cross-swapped roles: Mg²⁺ is the cofactor for ATP kinases, while Ca²⁺ triggers neuromuscular junction release and muscle contraction. Keeping their exact roles distinct prevents falling into these classic distractors.

🛡️ How to avoid the -1 mark: Mnemonic: "Mg for Magnesium = Metabolism & ATP"; "Ca for Calcium = Contraction & Communication (nerves)".

📖

Core NEET Syllabus Standard

National Eligibility cum Entrance Test (NEET UG) · The s-Block Elements Standard Benchmark

Core Scientific Principle Tested:

"Mg²⁺ is essential for all ATP-dependent enzymatic reactions, while Ca²⁺ maintains neuromuscular transmission and bone calcium homeostasis."

Syllabus Focus: Biological Importance of Magnesium and Calcium

Preserved in Rationalized Curriculum Syllabus & Academic Standards ↗

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NEET 2023 Chemistry Question 80 Solution

Question

The 30-Second Exam Hall Shortcut: ⚡ NCERT Biological Milestone: Daily Human Requirement is 200–300 mg (0.2–0.3 g)

Step-by-Step Rigorous Workflow & Mathematical Proof

Evaluate Statement (2): Daily Dietary Requirements

Evaluate Statement (1): Neuromuscular Signaling

Evaluate Statement (3): ATP Enzymatic Phosphate Transfer

Evaluate Statement (4): Biological Nature of Bone

360° Option Elimination Engine Key Feature

NTA Trap Alert: Swapping Ca²⁺ and Mg²⁺ Functions

Core NEET Syllabus Standard

Ready to attempt under real exam pressure?

🔗 Related Questions — The s-Block Elements

Anomalous Behavior of Beryllium: Structure of BeCl2 in Solid and Vapour Phases

Covalent Character and Solubility of Alkaline Earth Metal Halides: Fajan's Rules

Purification of Sodium Chloride: Common Ion Effect and Selective Crystallisation of NaCl

Biological Importance of Potassium (K+): Enzyme Activation & Sodium-Potassium Pump

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