Question

What is slaked lime?

Answer 1

Hint: The calcium-containing inorganic material which is primarily composed of calcium oxides of calcium hydroxides is known as lime. The lime originates its name from its earliest use as building mortar and has a sense of sticking or adhering.

Complete step by step solution:
-A soft, white, crystalline, the very slightly water-soluble powder obtained by the action of water on lime is known as slaked lime.
-In simple words, we can say that calcium hydroxide when mixed with water, a small portion of it dissolves forming a solution known as limewater, the part which remains undissolved and remains as a suspension is called milk of magnesia. The common name for a saturated solution of calcium hydroxide is lime water.
-Calcium hydroxide is a colourless crystal or white powdered inorganic compound. It is traditionally named by many names like slaked lime, milk of lime, calcium hydroxide, pickling lime, hydrated lime. Calcium hydrate, portlandite, and calcium hydroxide.
-In the lime industry, the term lime refers to rocks that contain 80% or more of calcium or magnesium carbonate including marble, chalk, oolite, and marl.
-Limestone is extracted from quarries or mines. A part of the extracted stone is sorted according to its chemical composition and their grain size is calcined to about $$1000{}^{\circ }C$$ in different types of lime kilns to produce limestone. The reaction for the production of lime is given as-
$CaC{O}_3\underset{1830{}^{\circ }F}{\overset{\mathrm{\Delta }}{\to }}CaO+C{O}_2$
-The calcium oxide, also known as quicklime produced in the above step is further hydrated and combined with water. This process is known as slaking. The hydrated lime is also slaked lime and the reaction for the production of slaked lime is given by-
$CaO+H_{2}O\to Ca{(OH)}_2$
-Slaking quicklime with just enough water to hydrate the quicklime, keeping it as a powder is known as hydrated lime and this method of preparing lime is called Dry slaking. When a slight excess of water is added to hydrate the quicklime to a form known as lime putty and this method of preparing lime is called Wet slaking.

Note: You should not get confused with some similar terms such as quicklime, slake lime, lime water, and soda-lime. Calcium oxide, CaO in its solid state is known as quicklime. Calcium oxide $Ca{(OH)}_2$ in the solid-state is known as slaked lime. The dilute solution of calcium hydroxide in water is known as lime water. The mixture of sodium hydroxide (also known as caustic soda) and calcium oxide (also known as quicklime) is known as soda lime.