A suitable solvent for iodine and naphthalene is

Analysis

This question tests your understanding of the principle of "like dissolves like" in chemistry. You are asked to identify a solvent that can dissolve both iodine ($I_2$) and naphthalene ($C_{10}H_8$).

Concept: Solubility and Polarity

• Iodine ($I_2$): This is a non-polar covalent molecule.
• Naphthalene ($C_{10}H_8$): This is also a non-polar organic compound.
• The Principle: In chemistry, polar solvents (like water) dissolve polar solutes and ionic compounds. Non-polar solvents dissolve non-polar solutes. Since both iodine and naphthalene are non-polar, they require a non-polar organic solvent to dissolve.

Step-by-Step Evaluation

1. Water ($H_2O$): Water is a highly polar solvent. It will not dissolve non-polar substances like iodine or naphthalene.
2. Ethanol ($C_2H_5OH$): While ethanol has some organic character, it is polar due to the hydroxyl (-OH) group. It is not the most suitable solvent for these specific non-polar solutes compared to non-polar organic solvents.
3. Carbon (IV) sulphide ($CS_2$): This is a non-polar solvent. It is an excellent solvent for iodine and many organic compounds. However, in the context of standard chemistry curricula (like JAMB), we must compare it with other options provided.
4. Benzene ($C_6H_6$): Benzene is a classic non-polar organic solvent. It is widely used in laboratories to dissolve non-polar substances like naphthalene and iodine.

In many Nigerian secondary school chemistry textbooks, benzene is the standard example cited for dissolving naphthalene and iodine.

Exam Tip

Remember the phrase "Like dissolves like."

• Polar solvents: Water, Ethanol.
• Non-polar solvents: Benzene, Carbon (IV) sulphide, Petrol, Kerosene. If you see iodine or naphthalene in a question, immediately look for an organic, non-polar solvent like benzene!