Some Important Compounds Of Calcium
Chapter Name : The S- Block Elements |
Sub Topic Code : 102_11_10_10_02 |
Topic Name : Some Important Compounds Of Calcium |
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Sub Topic Name : Calcium Hydroxide |
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Introduction
• Calcium hydroxide is prepared by adding water to quick lime, CaO. • It is a white amorphous powder. • It is sparingly soluble in water. • The aqueous solution is known as lime water and a suspension of slaked lime in water is known as milk of lime. • When carbon dioxide is passed through lime water it turns milky due to the formation of calcium carbonate. • Ca(OH)2 + CO2 à CaCO3 + H2O • On passing excess of carbon dioxide, the precipitate dissolves to form calcium hydrogencarbonate. • Milk of lime reacts with chlorine to form hypochlorite, a constituent of bleaching powder. • It is used in the preparation of mortar, a building material. • It is used in white wash due to its disinfectant nature. • It is used in glass making, in tanning industry, for the preparation of bleaching powder and for purification of sugar.
Pre-Requisites:
Alkali earth metals, elements, periodic table
Activity:
• It is used in the preparation of mortar, a building material. • It is used in white wash due to its disinfectant nature.
Real Life Question:
What is used for white washing walls?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Slaked lime | Calcium hydroxide. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| Periodic table | Look at the elements present in the group 2 of the periodic table.. |
Real life uses :
Used for white washing and making bleach.
Places to visit :
Construction site.
Practical examples around us
| Examples | Explainations |
|---|---|
| White washing, bleach | Calcium hydroxide is the main ingredient of white washing material and to make bleach. |
What you learn in Theory:
• Calcium hydroxide is prepared by adding water to quick lime, CaO. • It is a white amorphous powder. • It is sparingly soluble in water. • The aqueous solution is known as lime water and a suspension of slaked lime in water is known as milk of lime. • When carbon dioxide is passed through lime water it turns milky due to the formation of calcium carbonate. • Ca(OH)2 + CO2 à CaCO3 + H2O • On passing excess of carbon dioxide, the precipitate dissolves to form calcium hydrogencarbonate. • Milk of lime reacts with chlorine to form hypochlorite, a constituent of bleaching powder. • It is used in the preparation of mortar, a building material. • It is used in white wash due to its disinfectant nature. • It is used in glass making, in tanning industry, for the preparation of bleaching powder and for purification of sugar.
What you learn in Practice:
• Slaked lime is used to make mortar, glass making and bleaching powder.