Questions

After a span of 20 years, a Hindu politician, Darshan Lal, is set to take the role of a cabinet minister in Pakistan.  The new Prime Minister Shahaid Khaqan Abbasi formulated his cabinet and has appointed 65-year old Lal to lead coordination between four Pakistan provinces.

Lal reportedly used to practice as a doctor in Mirpur Mathelo town in Ghotki district of Sindh province.

Protect the consumer from the seller who cheat to sell his product.

The FTC’s Bureau of Consumer Protection stops unfair, deceptive and fraudulent business practices by collecting complaints and conducting investigations, suing companies and people that break the law, developing rules to maintain a fair marketplace, and educating consumers and businesses about their rights and responsibilities.

Graphite is a covalent-network type of crystalline solid.

There are two main categories of solids.

1. Crystalline solids and

2. Amorphous solids.

Crystalline solids are those in which the atoms, ions, or molecules that make up the solid exist in a regular, well-defined arrangement.

There are four types of crystalline solids :

Ionic solids :— Made up of positive and negative ions and held together by electrostatic attractions. They’re characterized by very high melting points and brittleness and are poor conductors in the solid state. An example of an ionic solid is table salt, NaCl.

Molecular solids :— Made up of atoms or molecules held together by London dispersion forces, dipole-dipole forces, or hydrogen bonds. Characterized by low melting points and flexibility and are poor conductors. An example of a molecular solid is sucrose.

Covalent-network (also called atomic) solids :— Made up of atoms connected by covalent bonds; the intermolecular forces are covalent bonds as well. Characterized as being very hard with very high melting points and being poor conductors. Examples of this type of solid are diamond and graphite, and the fullerenes. As you can see below, graphite has only 2-D hexagonal structure and therefore is not hard like diamond. The sheets of graphite are held together by only weak London forces!

Metallic solids :— Made up of metal atoms that are held together by metallic bonds. Characterized by high melting points, can range from soft and malleable to very hard, and are good conductors of electricity.