Question

Assertion: Quartz glass is a crystalline solid and quartz is an amorphous solid.
Reason: Quartz has a long-range order.
(A) Both Assertion and reasons are correct and reason is the correct explanation for the assertion.
(B) Both Assertion and reasons are correct, but reason is not the correct explanation for the assertion.
(C) Assertion is correct, but reason is incorrect.
(D) Both Assertion and reasons are incorrect.

Answer 1

Hint: If we know about quartz and quartz glass and in which state they both exist will help us to determine whether the given state is true or not. Crystalline substances will have a regular arrangement of the atoms while amorphous solid will have irregular arrangement of the atoms.

Complete step by step answer:
Before moving onto Assertion and Reasons, let us learn about quartz. Quartz is a very hard crystalline substance, which is composed of one mole of Silicon and two moles of oxygen, which is Silicon dioxide or . After feldspar, it is present abundantly in the earth’s surface along with many impurities such as Titanium, potassium, sodium and lithium. Quartz can occur in various colours such as yellow, pink, grey, white, etc. Quartz is a piezoelectric crystal. It can form both positive and negative charge at the edges of the prism when subjected to a high pressure.
We know that crystalline substances will have a regular arrangement of atoms in the crystal and are held by strong intermolecular force. Hence quartz being a crystalline substance it will have a regular arrangement of the atoms. While amorphous substances will not have regular arrangement of atoms in the crystal. The Quartz glass being amorphous solid it will not have a regular arrangement. It is formed by fusing and later on cooling the substance.
Hence the Assertion and reason are incorrect.

Therefore, the correct answer is option (D) Both Assertion and reasons are incorrect.

Additional information:
Comparison of Amorphous and crystalline solids

AMORPHOUS	CRYSTALLINE
Have an irregular arrangement of atoms in the solid.	Have regular arrangement of atoms in the crystal.
It is isotropic in nature	It is anisotropic in nature
It can melt over different temperatures.	It has a sharp melting point.
Example: Glass	Example: Diamond.

Note: Quartz can be used for various purposes such as:
- It can be used in the petroleum industry.
- It can be used for the making of glass.
- It can be used in abrasives.
- Can be used for making foundry sand.