Ask a New Question
Menu

Chalk did not dissolve in water or in toluene, give a brief account of how you would use these difference in properties to obtain separate pure sample of chalk

1 answer

To obtain a pure sample of chalk using its insolubility in both water and toluene, you can employ a simple separation technique based on the physical differences between chalk and other substances. Here’s a step-by-step account of the procedure:

Materials Needed:

  • Mixture of chalk and other soluble substances (e.g., sugar, salt)
  • Water
  • Toluene
  • Filtration apparatus (filter paper and funnel)
  • Evaporating dish (if needed)

Procedure:

  1. Dissolution in Water:

    • First, take the mixture containing chalk and the soluble substances. Add water to the mixture and stir well.
    • The soluble substances (like sugar or salt) will dissolve in the water, while the chalk will remain undissolved as a solid.

  2. Filtration:

    • Set up a filtration apparatus with a funnel and filter paper.
    • Pour the mixture through the filter. The chalk (insoluble) will remain on the filter paper, while the dissolved substances will pass through into the collecting flask as a filtrate.

  3. Washing the Chalk:

    • To ensure that all soluble impurities are removed from the chalk, wash the residue on the filter paper with a little more water. This helps to remove any remaining dissolved substances that may adhere to the chalk particles.

  4. Drying the Chalk:

    • Carefully collect the chalk from the filter paper and place it in a dry container. Allow it to air dry or gently heat it to ensure all moisture is removed. You now have a pure sample of chalk.

  5. Dissolution in Toluene:

    • If the original mixture had organic solvents or substances soluble in toluene, you could also extract those using toluene after obtaining the chalk. Since chalk does not dissolve in toluene, it would not interfere with the extraction process. However, since you have already collected pure chalk, this step may be for further separation of other components in the initial mixture.

Summary:

By utilizing the water solubility of certain substances and the insolubility of chalk in both water and toluene, you can effectively separate chalk from a mixture. Filtration is the key method used to isolate the chalk from soluble impurities, resulting in a pure sample of chalk.