Question

Which of the following are not compounds?

• A. Chlorine gas
• B. Potassium chloride
• C. Iron
• D. Iron sulfide
• E. Aluminum
• F. Iodine

Answer 1

Answer: (A), (C), (E), (F)

Iodine

The explanation of the correct options:

A)Chlorine gas (${\mathrm{Cl}}_2$)

• Elements are defined as substances that cannot be broken down further into any components by a simple chemical reaction and exist in that state. Each element is made up of atoms having different protons and neutrons in them. example: $\mathrm{S},\mathrm{C},{\mathrm{O}}_2$
• A compound is defined as a mixture of elements chemically bonded by two or more of these elements in fixed proportions and varying individual ratios. examples: $\mathrm{HCl},{\mathrm{H}}_2\mathrm{O},{\mathrm{FeSO}}_4$
• Therefore,Chlorine gas(${\mathrm{Cl}}_2$) is an element.

C)Iron($\mathrm{Fe}$)

• Elements are the pure substance of one type. Iron is present as a solid in its elemental form.
• Iron here is present in its elemental state since it cannot be further broken down.

E)Aluminum($\mathrm{Al}$)

• Aluminium cannot be further broken down into any compound because it is a pure substance, in its elemental state.
• It is solid in its elemental form.

F) Iodine(${\mathrm{I}}_2$)

• Although iodine is present as ${\mathrm{I}}_2$ , still it is present in its elemental state.
• It is solid in its elemental form.

The explanation of incorrect options:

B)Aluminium chloride(${\mathrm{AlCl}}_3$)

• ${\mathrm{AlCl}}_3$ is a compound.
• It is a covalent compound.

D) iron sulfide ($\mathrm{FeS}$)

• $\mathrm{FeS}$ is a compound.
• It is an ionic compound and iron is in$+2$ the state.

Hence, the correct options are A)Chlorine gas, C)Iron, E)Aluminum, and F) Iodine