Water (H2O) contains oxygen as a constituent. By the same chemical-constituent logic, common salt contains which element?

Introduction / Context:
This analogy maps a compound to a characteristic element within it. Water (H2O) contains oxygen; common salt (table salt) is sodium chloride (NaCl) and contains sodium. We must retain the “substance → constituent element” relation.

Given Data / Assumptions:
We use everyday chemical names: water, salt (table salt), and their typical compositions.

Concept / Approach:
Identify the standard formula: NaCl. From salt → sodium chloride, extract the element “sodium” as the target. Avoid non-elements or biologically oriented distractors like proteins. Iron/calcium/sulfur appear in other compounds but not in NaCl as primary elements.

Step-by-Step Solution:

Verification / Alternative check:
Basic chemistry confirms NaCl composition.

Why Other Options Are Wrong:
They are not constituents of table salt or are not elements in this context.

Common Pitfalls:
Overthinking ionic vs covalent distinctions; the exam expects the everyday formula mapping.

Final Answer:
Sodium