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If a limestone piece is dipped in water, a bubble evolves. The bubbling is due to
Explanation
When a piece of limestone (calcium carbonate, CaCO3) is dipped in water, bubbles evolve due to the release of carbon dioxide (CO2). Limestone is a porous sedimentary rock that naturally contains air and carbon dioxide trapped within its pores [t4]. Additionally, carbon dioxide from the atmosphere dissolves in water to form a weak carbonic acid (H2CO3) [c3][t5]. This acidic solution reacts with the calcium carbonate in the limestone to form soluble calcium bicarbonate (Ca(HCO3)2) [c1][t2]. The chemical equilibrium between the carbonate, bicarbonate, and dissolved CO2 often results in the release of CO2 gas as bubbles [t1][t7]. This process is a fundamental part of the limestone cycle and the natural weathering of rocks, where CO2 is released or absorbed depending on the concentration and temperature of the solution [t2][t6].
Sources
- [1] Science , class X (NCERT 2025 ed.) > Chapter 2: Acids, Bases and Salts > Activity 2.5 > p. 21
- [2] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 18: Ocean Acidification > How it reacts? > p. 264