The incorrect statement among the following regarding crystalline solid is -
1. | Definite and characteristic heat of fusion. |
2. | Isotropic nature. |
3. | A regular periodically repeated pattern of arrangement of constituent particles in the entire crystal. |
4. | A true solid. |
An example of amorphous solid among the following is -
1. Graphite (C)
2. Quartz glass (SiO2)
3. Chrome alum
4. Silicon carbide (SiC)
Incorrect statement among the following about amorphous solids is -
1. | On heating they may become crystalline at a certain temperature. |
2. | They may become crystalline on keeping for a long time. |
3. | Amorphous solids can be moulded by heating. |
4. | They are anisotropic in nature. |
Select the correct option based on statements below:
Assertion (A): | Crystalline solids have sharp melting points. |
Reason (R): | Crystalline solids have definite enthalpies of fusions. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
Iodine crystals are classified as-
1. Metallic solids.
2. Ionic solids.
3. Molecular solids .
4. Covalent solids.
TiO2 is a well-known example of:
1. Triclinic system.
2. Tetragonal system.
3. Monoclinic system.
4. None of the above.
The unit cell dimensions of a cubic lattice (edges a, b, c and the angles between them, α, β, γ) are :
1. a = b = c,
2. a = b c,
3. a = b = c,
4. a b c,
The correct option for the number of body centred unit cells in all 14 types of Bravais lattice unit cells is :
1. 2
2. 3
3. 7
4. 5
The mass of a unit cell of CsCl corresponds to:-
1. 8Cs+ and Cl-
2. 1Cs+ and 6Cl-
3. 1Cs+ and 1Cl-
4. 4Cs+ and Cl-
A compound is formed by cation C and anion A. The anions form hexagonal close packed (hcp) lattice and the cations occupy 75 % of octahedral voids. The formula of the compound is:
1.
2.
3.
4.