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What is the chemical formula of the product formed when quicklime (CaO) reacts with water?
Ca(OH)2тАЛ
CaCO3тАЛ
CaO2тАЛ
CaH2тАЛ
Ca(OH)2тАЛ
When quicklime (calcium oxide, CaO) reacts with water, it undergoes a vigorous combination reaction to form slaked lime (calcium hydroxide, Ca(OH)2тАЛ), releasing a significant amount of heat in the process.
When quicklime (calcium oxide, CaO) reacts with water, it undergoes a vigorous combination reaction to form slaked lime (calcium hydroxide, Ca(OH)2тАЛ), releasing a significant amount of heat in the process.
Adding water to quicklime is similar to preparing plaster or mixing traditional whitewash for walls, where heat is immediately generated as the dry powder turns into a smooth alkaline paste.
Oxide + Water = Hydroxide (CaO+H2тАЛOтЖТCa(OH)2тАЛ)
CaO+H2тАЛOтЖТCa(OH)2тАЛ+Heat тАФ Exothermic hydration of quicklime
This is an exothermic combination reaction where calcium oxide chemically combines with water molecules. The reaction CaO+H2тАЛOтЖТCa(OH)2тАЛ results in calcium hydroxide, which forms a clear solution or suspension known commonly as limewater or milk of lime.
Quicklime is chemically known as calcium oxide (CaO).
Slaked lime is chemically known as calcium hydroxide (Ca(OH)2тАЛ).
The reaction is highly exothermic, causing the water to hiss, bubble, and heat up.
Aqueous solution of slaked lime is basic and turns red litmus blue.
Whitewashing of walls
Manufacture of bleaching powder
Neutralization of acidic soils in agriculture
| Feature | Quicklime | Slaked Lime |
|---|---|---|
Chemical Formula | CaO | Ca(OH)2тАЛ |
Chemical Name | Calcium oxide | Calcium hydroxide |
Option B (CaCO3тАЛ) is calcium carbonate, which forms later when slaked lime on walls reacts slowly with carbon dioxide in the air.
Option C (CaO2тАЛ) is calcium peroxide and Option D (CaH2тАЛ) is calcium hydride, neither of which is the primary hydration product of quicklime.
A is correct тАФ Quicklime reacts with water to form calcium hydroxide, commonly known as slaked lime.
Always remember that metal oxides are basic in nature and react with water to form alkaline solutions, a frequently tested concept in railway and state-level competitive exams.
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