AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.
The three naturally occurring forms of calcium carbonate mentioned in the chapter are marble, the thin layer formed on whitewashed walls, and calcium carbonate deposited in nature.
(As per the chapter, marble and the calcium carbonate layer on whitewashed walls share the formula CaCO₃. The chapter specifically names marble as a naturally occurring form.)
Correction: The chapter mentions only marble explicitly as a naturally occurring form with formula CaCO₃. The passage does not list three naturally occurring forms.
> Based strictly on the source passage: The chapter mentions marble (CaCO₃) as a naturally occurring form of calcium carbonate.
Source: Chapter 1, Section 1.2.1
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The source passage only explicitly names marble as a naturally occurring form of CaCO₃. The question asks for three, but the provided passages do not support three distinct naturally occurring forms. If this question appears in your textbook exercise, it likely refers to marble, limestone, and chalk — all CaCO₃ — which are standard NCERT knowledge, but these are not all named in the given passage. In the exam, if the passage is the only source, write what the passage supports. If it is a general knowledge question from the chapter, the expected answer is: marble, limestone, and chalk.