Question

A) In a experiment to estimate the size of a molecule of oleic acid 1 ml of oleic acid is dissolved in 19ml of alcohol. Then 1 ml of this solution is diluted to 20 ml by adding alcohol Now 1 drop of this diluted solution is placed on water on a shallow through. The solution spreads over the surface of water forming one molecule thick layer

Now, lycopodium powder is sprinkled evenly over the film and its diameter is measured. Knowing the volume of the drop and area of the film we can calculate the thickness of the film which will give us the size of oleic acid molecule. Read the passage carefully and answer the following question. Why do we dissolve oleic acid in alcohol?


B) In an experiment to estimate the size of a molecule of oleic acid 1ml of oleic acid is dissolved in 19mL . of alcohol . Then 1 mL of this solution is diluted to 20 mL adding alcchol. Now 1 drop of this diluted solution is placed on water in a shallow trough . The solution spreads over the solution surface of water forming one molecule thick layer.

Now, lycopodium powder is sprinkled evenly over the film and its diameter is measured. Knowing the volume of the drop and area of the film we can calculate the thickness of the film which will give us the size of oleic acid molecule. Read the passage carefully and answer the following question. What is the role of lycopodium powder?


C) In an experiment to estimate the size of a molecule of oleic acid 1ml of oleic acid is dissolved in 19mL . of alcohol . Then 1 mL of this solution is diluted to 20 mL adding alcchol. Now 1 drop of this diluted solution is placed on water in a shallow trough . The solution spreads over the solution surface of water forming one molecule thick layer.

Now, lycopodium powder is sprinkled evenly over the film and its diameter is measured. Knowing the volume of the drop and area of the film we can calculate the thickness of the film which will give us the size of oleic acid molecule. Read the passage carefully and answer the following question. What would be the volume of oleic acid in each mL of solution prepared?

D)In an experiment to estimate the size of a molecule of oleic acid 1ml of oleic acid is dissolved in 19mL . of alcohol . Then 1 mL of this solution is diluted to 20 mL adding alcchol. Now 1 drop of this diluted solution is placed on water in a shallow trough . The solution spreads over the solution surface of water forming one molecule thick layer.

Now, lycopodium powder is sprinkled evenly over the film and its diameter is measured. Knowing the volume of the drop and area of the film we can calculate the thickness of the film which will give us the size of oleic acid molecule. Read the passage carefully and answer the following question. How will you calculate the volume of n drops of this solution of oleic acid?


E)In an experiment to estimate the size of a molecule of oleic acid 1ml of oleic acid is dissolved in 19mL . of alcohol . Then 1 mL of this solution is diluted to 20 mL adding alcchol. Now 1 drop of this diluted solution is placed on water in a shallow trough . The solution spreads over the solution surface of water forming one molecule thick layer.

Now, lycopodium powder is sprinkled evenly over the film and its diameter is measured. Knowing the volume of the drop and area of the film we can calculate the thickness of the film which will give us the size of oleic acid molecule. Read the passage carefully and answer the following question. What will be the volume of oleic acid in one drop of this solution?

Answer 1

A) To get a molecular level we have to reduce the concentration of oleic acid by dissolving it in a proper solvent.

Oleic acid is an organic compound so cannot be dissolved in ionic solvent water. It can dissolve in organic solvent alcohol.

Therefore, Oleic acid does not dissolve in water, hence it is dissolved in alcohol.

Final Answer: Oleic acid does not dissove in water hence it is dissolved in alchol.


B) Lycopodium powder is used to distinguish the region of oleic acid and water by forming a boundary between the two. It also weakens the surface tension of the oleic acid and allows the layer to expand to its maximum size

Final answer : When lycopodium powder is spread on water . it spread on the entire surface


C) As given 20 mL ( 1 mL oleic acid +19 mL alchol) contains 1mL of oleic acid , Oleic acid in each mL of the solution = $\frac{1}{20}$ mL

Further , as this 1mL diluted to 20 mL by adding alchol . in each ml of solution prepared, Volume of oleric acid = $\frac{1}{20}mL\times \frac{1}{20}mL=\frac{1}{400}mL$

Final answer: Volume of oleic acid = $\frac{1}{400}mL$

D) For determining the volume of n drops of this solution an instrument called burette will be used. The burette will be filled to a desired volumes as marked on the burette scale.

The burette allows the solution to be released drop by drops and thus n drops will be counted, the final value of the volume will be measure through burette scale and then substacted from the initial value which will be the volume of the no of drops.

Volume of n drops = Initial value – Final value

Final Answer: By means of a burette and measuring cylinder and measuring the number of drops.


E) Let there be n drops in 1ml of this solution which be measured by using the burette. We know that in 1mL of this solution there is 0.0025 mL of oleic acid Then , volume of oleic acid in drops
= $\frac{1}{400}=0.0025mL$

= $\frac{1}{400n}mL$

Final answer : Volume of oleic acid in one drop will be

($\frac{1}{400n}$ mL)