Solid A is a very hard electrical insulator in solid as well as in molten state and melts at extremely high temperature. What type of solid is it?

1. H-bonded molecular solid

2. Ionic solid

3. Covalent or network solid

4. Metallic solid

The incorrect statement among the following regarding crystalline solid is -

An example of amorphous solid among the following is -

1. Graphite (C)

2. Quartz glass (SiO₂)

3. Chrome alum

4. Silicon carbide (SiC)

Which of the following arrangements shows the schematic alignment of magnetic moments of antiferromagnetic substances? 

1. $\overline{)\uparrow }$ $\overline{)\uparrow }$ $\overline{)\uparrow }$ $\overline{)\uparrow }$ $\overline{)\uparrow }$ $\overline{)\uparrow }$

2. $\overline{)\downarrow }$ $\overline{)\downarrow }$ $\overline{)\downarrow }$ $\overline{)\downarrow }$ $\overline{)\downarrow }$ $\overline{)\downarrow }$

3. $\overline{)\uparrow }$ $\overline{)\uparrow }$ $\overline{)\downarrow }$ $\overline{)\uparrow }$ $\overline{)\uparrow }$ $\overline{)\downarrow }$

4. $\overline{)\uparrow }$ $\overline{)\downarrow }$ $\overline{)\uparrow }$ $\overline{)\downarrow }$ $\overline{)\uparrow }$ $\overline{)\downarrow }$

Incorrect statement among the following about amorphous solids is -

Iodine molecules are held in the crystals lattice by ........ .

1.  London forces.

2.  Dipole-dipole interactions.

3.  Covalent bonds.

4.  Coulombic forces.

Network solid, among the following, is :

1. SO₂(solid)

2. I₂

3. Diamond

4. H₂O(ice)

I. Mg(s)

II. TiO(s)

III. I₂(s)

IV. H₂O(s)

The insulator among the given examples is -

1. Only I

2. Only II

3. III and IV

4. II, III, and IV

Graphite is a good conductor of electricity due to the presence of ......... .

(1) Lone pair of electrons.

(2) Free valence electrons.

(3) Cations.

(4) Anions.

Graphite cannot be classified as ...........

1.  Conducting solid.

2.  Network solid.

3.  Covalent solid.

4.  Ionic solid.