Charcoal is used in the decolourization of sugar because of its

Step 1: Analyze the question The question asks why charcoal can remove colour from sugar solutions. Raw sugar syrup contains coloured impurities, and charcoal removes them.

Step 2: Explain the concept

• Adsorption is the sticking of molecules (gas, liquid or dissolved particles) onto the surface of a solid.
• Absorption is when a substance is taken up into the bulk of another, like a sponge soaking up water.

Activated charcoal is highly porous and has a very large surface area. The coloured impurity molecules in the sugar syrup stick to its surface. The same property is used in gas masks, water purification and the removal of poisons in the stomach.

Step 3: Check each option

• A. Absorption: Wrong. The colour molecules do not penetrate the charcoal's bulk. They attach to its surface.
• B. Amorphous: Charcoal is indeed an amorphous form of carbon, but being amorphous (having no regular crystal structure) is not what removes colour.
• C. Oxidizing: Wrong. Charcoal is a reducing agent, not an oxidizing one, and decolourization here is not by oxidation.
• D. Adsorption: Correct. Coloured impurities are adsorbed onto the charcoal's large surface area, leaving the sugar solution colourless.

Step 4: Answer The correct option is D. adsorption property.

Exam tip: Remember "AD" = "ADhere to the surface". Adsorption is a surface effect, while absorption is soaking in. WAEC often tests this pair, so watch the spelling carefully.