Chemistry Quiz: Borax and Boric Acid

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Questions and Answers

What is the nature of an aqueous solution of borax?

Basic

Acidic

Amphoteric (correct)

Neutral

Why is boric acid polymeric?

Due to its geometry

Due to its monobasic nature

Due to its acidic nature

Due to the presence of hydrogen bonds (correct)

What is the type of hybridization of boron in diborane?

sp3

dsp2

sp2

sp (correct)

What is the thermodynamically most stable form of carbon?

Graphite Signup and view all the answers

What oxidation states do elements of group 14 exhibit?

+2 and +4 Signup and view all the answers

What is the product formed when RSiCl3 is used as the starting material for the manufacture of silicones?

RSi(OH)3 Signup and view all the answers

What is the primary occurrence of boron in nature?

As orthoboric acid (H3BO3) Signup and view all the answers

What is another name for Na2B4O7·10H2O?

Borax Signup and view all the answers

Where is borax commonly found in India?

Both A and B Signup and view all the answers

What is the chemical formula for kernite?

Na2B4O7·4H2O Signup and view all the answers

What is the primary use of borax?

In the production of fiberglass Signup and view all the answers

What is H3BO3 also known as?

Boric acid Signup and view all the answers

What is the common occurrence of boron in nature?

As compounds like borax and kernite Signup and view all the answers

What is the pH of borax?

Basic Signup and view all the answers

What is the percentage of boron in the earth's crust by mass?

0.0001% Signup and view all the answers

What is the most abundant metal in the earth's crust?

Aluminium Signup and view all the answers

What is the formula of the mineral cryolite?

Na3AlF6 Signup and view all the answers

What is the percentage of silicon in the earth's crust by mass?

27.7% Signup and view all the answers

What is the formula of bauxite?

Al2O3.2H2O Signup and view all the answers

What is the oxidation state of boron in its compounds?

Not mentioned Signup and view all the answers

What is the percentage of oxygen in the earth's crust by mass?

45.5% Signup and view all the answers

Study Notes

Group 13 Elements: The Boron Family

Boron is a typical non-metal, while aluminium is a metal, but shows many chemical similarities to boron.
Gallium, indium, and thallium are almost exclusively metallic in character.
Boron is a fairly rare element, mainly occurring as orthoboric acid, borax, and kernite.
Borax occurs in Puga Valley (Ladakh) and Sambhar Lake (Rajasthan) in India.
The abundance of boron in the earth's crust is less than 0.0001% by mass.
There are two isotopic forms of boron: B (19%) and B (81%).

Properties of Boron Compounds

An aqueous solution of borax is basic.
Boric acid is polymeric due to the presence of hydrogen bonds.
The type of hybridisation of boron in diborane is sp2.

Group 14 Elements: The Carbon Family

The most stable form of carbon is graphite thermodynamically.
Elements of group 14 exhibit oxidation states of +4 and +2.
Carbon exhibits negative oxidation states.
Carbon forms two important oxides: CO (neutral) and CO2 (acidic).
Carbon monoxide has a lone pair of electrons on C and forms metal carbonyls.
Carbon is poisonous due to the higher stability of its haemoglobin complex compared to that of oxyhaemoglobin complex.

Other Key Facts

Aluminium is the most abundant metal and the third most abundant element in the earth's crust after oxygen and silicon.
Bauxite, Al2O3. 2H2O, and cryolite, Na3AlF6, are important minerals of aluminium.