Some Important Compounds Of Boron
Chapter Name : The P- Block Elements |
Sub Topic Code : 102_11_11_04_02 |
Topic Name : Some Important Compounds Of Boron |
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Sub Topic Name : Orthoboric Acid |
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Introduction
• Orthoboric acid, H3BO3 is a white crystalline solid, with soapy touch. • It is sparingly soluble in water but highly soluble in hot water. • It can be prepared by acidifying an aqueous solution of borax. • It is also formed by the hydrolysis (reaction with water or dilute acid) of most boron compounds (halides, hydrides, etc.). • It has a layer structure in which planar BO3 units are joined by hydrogen bonds • Boric acid is a weak monobasic acid. • It is not a protonic acid but acts as a Lewis acid by accepting electrons from a hydroxyl ion. • On heating, orthoboric acid above 370K forms metaboric acid, HBO2 which on further heating yields boric oxide, B2O3.
Pre-Requisites:
Elements, periodic table, Group
Activity:
• Group 13 has aluminium, boron which are important industrial elements.
Real Life Question:
What is boron used for?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| P block elements | Have the last electron in the outermost p orbital. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| Boric acid | Used for killing insects. |
Real life uses :
• An important compound of boron is boric acid used for killing insects.
Places to visit :
Chemistry lab, kitchen.
Practical examples around us
| Examples | Explainations |
|---|---|
| Boric acid | Used for killing insects. |
What you learn in Theory:
• Orthoboric acid, H3BO3 is a white crystalline solid, with soapy touch. • It is sparingly soluble in water but highly soluble in hot water. • It can be prepared by acidifying an aqueous solution of borax. • It is also formed by the hydrolysis (reaction with water or dilute acid) of most boron compounds (halides, hydrides, etc.). • It has a layer structure in which planar BO3 units are joined by hydrogen bonds • Boric acid is a weak monobasic acid. • It is not a protonic acid but acts as a Lewis acid by accepting electrons from a hydroxyl ion. • On heating, orthoboric acid above 370K forms metaboric acid, HBO2 which on further heating yields boric oxide, B2O3.
What you learn in Practice:
• Group 13 has aluminium, boron which are important industrial elements.