Hello, I'm Dr. Alex, a chemist with a focus on inorganic compounds. I've spent years studying the properties and reactions of various chemical substances, and I'm happy to share my expertise with you today.

You want to know about the formula of lime water, and it's a question that often causes a bit of confusion. Let me clarify it for you.

First, we need to differentiate between two types of "lime":


1. Quicklime (Calcium Oxide, CaO): This is a white, caustic, alkaline, crystalline solid at room temperature. Quicklime is produced industrially by the thermal decomposition of materials like limestone, chalk, or seashells that contain calcium carbonate (CaCO3; mineral calcite) in a lime kiln. This process of calcining, which requires a temperature of around 825 °C (1,517 °F), drives off carbon dioxide (CO2), leaving quicklime:
CaCO3 (s) → CaO (s) + CO2 (g).

2. **Slaked Lime (Calcium Hydroxide, Ca(OH)2):** When we talk about "lime water," we are actually referring to a solution of calcium hydroxide in water. Calcium hydroxide is produced by the reaction of quicklime (CaO) with water. This process, called "slaking," is an exothermic reaction that releases a significant amount of heat:
CaO (s) + H2O (l) → Ca(OH)2 (aq) + heat.

Therefore, **lime water is a dilute solution of calcium hydroxide (Ca(OH)2) in water**.

It's important to note that calcium hydroxide has limited solubility in water. At room temperature, a saturated solution will have a concentration of about 0.02 molar (approximately 1.5 grams of calcium hydroxide per liter of water). The solution is called lime water and is a clear and colorless solution. The suspension of calcium hydroxide particles in water is called milk of lime and appears milky or cloudy.

Here are some key properties and uses of lime water:

* Alkaline Nature: Lime water is alkaline, meaning it has a pH greater than 7. It can neutralize acids, making it useful in various applications, including treating acidic soil and industrial wastewater treatment.

* Calcium Source: Lime water is a source of calcium ions. It's used in food preparation, such as in the nixtamalization process for corn, where it enhances the nutritional value and availability of niacin.

* Carbon Dioxide Test: One of the most well-known uses of lime water is as a test for the presence of carbon dioxide. When carbon dioxide is bubbled through lime water, it reacts with the calcium hydroxide to form calcium carbonate, which precipitates out of solution as a milky white substance. This reaction is represented by the following equation:
Ca(OH)2 (aq) + CO2 (g) → CaCO3 (s) + H2O (l)

* Medical Uses: Historically, lime water has been used for medicinal purposes due to its antacid properties. It can neutralize stomach acid and relieve symptoms of heartburn and indigestion. However, its use for these purposes has declined in modern medicine with the availability of more effective and palatable antacids.

Let me know if you have any further questions or if there's anything else I can help you with regarding lime water or other chemical compounds.
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Calcium hydroxide (traditionally called slaked lime) is an inorganic compound with the chemical formula Ca(OH)2. It is a colorless crystal or white powder and is obtained when calcium oxide (called lime or quicklime) is mixed, or slaked with water.read more >>