Diamond is covalent, yet it has a high melting point, due to:
| 1. | A hexagonal planar structure |
| 2. | Three-dimensional network involving strong C—C bonds |
| 3. | C-C double bond |
| 4. | Octahedral arrangement of carbon atoms |
Which of the following explains why diamond is extremely hard while graphite is soft, even though both are made of carbon atoms?
| 1. | Diamond has carbon-carbon double bond while graphite has carbon-carbon single bond |
| 2. | Diamond is ionic whereas graphite is covalent |
| 3. | Diamond has a strong covalent bond with regular tetrahedron pattern |
| 4. | Certain atoms in diamond are smaller in size |
Mark the oxide which is amphoteric in character:
1. CO2
2. CO
3. SnO2
4. CaO
C60, an allotrope of carbon contains :
1. 16 hexagons and 16 pentagons.
2. 12 hexagons and 20 pentagons.
3. 18 hexagons and 14 pentagons.
4. 20 hexagons and 12 pentagons.
| 1. | Carbon has the tendency to form chains and rings with itself. |
| 2. | Silicon and Germanium are useful in semiconductor industry. |
| 3. | Boron trifluoride is a Lewis acid. |
| 4. | Common oxidation states of group 14 elements are +1 and +3. |
Match the species in Column-I with their corresponding hybridisation in Column-II:
| Column-I (Species) | Column-II (Hybridisation) | ||
| A. | Boron in | i. | sp2 |
| B. | Aluminium in | ii. | sp3 |
| C. | Carbon in Buckminsterfullerene | iii. | sp3d2 |
| D. | Germanium in |
Codes:
| A | B | C | D | |
| 1. | ii | iii | i | iii |
| 2. | i | i | iii | ii |
| 3. | iii | ii | ii | i |
| 4. | i | iii | ii | iii |