Free Chromatography MCQs with Answers

1. The mobile phase in paper chromatography is usually:

• A. A non-polar organic solvent
• B. Water
• C. Sulfuric acid
• D. Silver nitrate

Explanation: The correct answer is a non-polar organic liquid. In paper chromatography, the mobile phase is typically a non-polar organic solvent that moves up the paper, carrying the different components of the mixture with it. This helps separate the components based on their affinity to the stationary phase, which is usually water (a polar substance) within the paper. This polarity difference is crucial for separation. Water is incorrect as it serves as the stationary phase. Sulphuric acid and silver nitrate are not used as mobile phases in this technique due to their inappropriate properties for chromatography.

2. Paper chromatography is used for:

• A. Elemental Analysis
• B. Qualitative Analysis
• C. Industrial Purification
• D. Structural Analysis

Explanation: Explanation:Chromatography is very useful for organic synthesis for separation, purification, and isolation of products. They are equally important for quantitative and qualitative analysis and for determination of purity of a substance. Elemental analysis involves determining the elemental composition of a substance. Paper chromatography is not used for this purpose since it separates components based on their physical properties rather than their elemental composition.Industrial purification typically involves separating and purifying a specific component from a mixture at a large scale. Paper chromatography is not commonly used for industrial purification. Paper chromatography is used for qualitative analysis, not for structural analysis.

3. The purity of a substance can be identified by:

• A. Sublimation
• B. Filtration
• C. Chromatography
• D. Solvent extraction

Explanation: A is incorrect as sublimation purifies solids rather than identify themB is incorrect as filtration separates insoluble solutes from solvents.C is correct as chromatography is a tool to separate different solvents in a solute and their purification.D is incorrect as solvent extraction only extracts solutes,but doesnt identify them.

4. Which one is used as stationary phase in paper chromatography?

• A. Alcohol
• B. Adeline
• C. Piece of paper
• D. Water absorbed on paper

Explanation: Water absorbed on paper: This option is correct. In paper chromatography, the stationary phase is usually achieved by impregnating the paper with water or a suitable aqueous solution. The water absorbed on the paper fibers acts as the stationary phase, while the mobile phase (solvent) carries the components of the sample along the paper.

5. Which of the statements about paper chromatography is not correct:

• A. Paper chromatography is an example of partition chromatography.
• B. Paper chromatography is most commonly used to separate biologically active substances.
• C. Paper chromatography can also be applied for separating some inorganic ions.
• D. Paper chromatography is always used for quantitative analysis.

Explanation: There are limitations to paper chromatography that include;Large quantities of sample cannot be applied on paper chromatography.In quantitative analysis paper chromatography is not effective.Complex mixture cannot be separated by paper chromatography.