Explanation:

- Option 1: Common salt

Sodium chloride is the scientific name for common salt. It consists of sodium (Na) and chloride (Cl) ions, and it's widely used in cooking and food preservation.

- Option 2: Soft coke

Soft coke is a type of coal that is used as a fuel. It is not related to sodium chloride.

- Option 3: Rust

Rust is iron oxide, which occurs when iron reacts with oxygen and moisture. It has no relation to sodium chloride's composition.

- Option 4: Chalk

Chalk is primarily composed of calcium carbonate (CaCO3), not sodium chloride.