Chromatographic separation of substances from a mixture depends on the basis of :

Question

Accepted Answer

Chromatographic separation of substances from a mixture is fundamentally based on the different extents of their adsorption by the same material, which is why Option 4 is the correct answer. Here is a detailed explanation:

1. **Explanation for Option 4:**
   Chromatography is a technique used to separate components of a mixture based on their differential adsorption to a stationary phase while being carried by a mobile phase. The stationary phase is typically a solid or a viscous liquid, and the mobile phase can be a liquid or a gas. As the mixture moves through the stationary phase, different substances in the mixture adsorb to the stationary phase to varying extents. This differential adsorption causes the substances to travel at different rates, leading to their separation. The key principle here is the varying degree of interaction (adsorption) each component has with the stationary phase, which is why Option 4 is correct.

2. **Explanation for why other options are incorrect:**

- **Option 1: Their solubilities in the same solvent**
     While solubility can play a role in the initial dissolution of substances in the mobile phase, chromatography primarily relies on the interaction between the substances and the stationary phase, not just their solubility in the solvent. Solubility alone does not account for the separation process in chromatography.

- **Option 2: The difference in their volatilities**
     Volatility refers to how readily a substance vaporizes. While volatility is a key factor in techniques like distillation, it is not the primary basis for separation in chromatography. Chromatography focuses on the interaction between the substances and the stationary phase, rather than their tendency to vaporize.

- **Option 3: Their different colours under similar conditions**
     The color of substances is not a factor in their separation during chromatography. While colored substances can be visually tracked during the process, the separation itself is not based on color differences. Chromatography separates substances based on their adsorption characteristics, not their color.

In summary, the correct basis for chromatographic separation is the different extent of adsorption of substances by the same material, which is accurately captured by Option 4.