Question

Suppose you were given a mixture of n-octane, sodium iodide and water to separate. Using the information gathered for these and similar compounds in this experiment, and using what you know about the properties of these materials from other contexts, outline a procedure that could be used to do a quantitative separation of these three materials. Your procedure should be specific enough, that if followed, someone could determine the amount (mass) of each of the three materials present in the mixture.

Answer 1

We know the mixture contains n-octane,sodium iodide,and water

Properties of n-octane:

• It is immisibleand thus forms a separate layerin water which is physically distinct

• Density is 0.703g/cm^-3 which is less than water and hence floats above water

Properties of NaI:

• It is water soluble and thus does not form any physically distinct l layer in water

• solubility is 184.2 g of NaI per 100g of water at 25 °C

Whe NaI is put in water it gets soluble and hence we can't see NaI with naked eyes and mixing these 3 would result in 2 layers one will be of n-octane which will float on water dissolved with NaI .

We can separate these 3 first using separating funnel .The funnel is used to separate the immisible liquids . We will pour the water dissolved with NaI in funnel and then we will pour the n-octane we will see n-octane will floats above the water when we will allow the mixture to rest for 20-30 mins .There is a stop cock at the bottom of the funnel. Now we will start to seprate . We will take a flask below the funnel and open the stop cock we will see water dissolved with NaI will start to descend and when whole of it descend into the flask we will close the stop cock and we will be have the flask named as (1).

Now we will see the funnel has only n-octane and we will take another flask and allow it to descend whole of it into the flask named (2) thus we will see n-octane is seprated from the mixture and its mass can be calculated then .

Now we will take flask (1) and start it to heat  as it contain water and dissolved NaI and now when we start to heat the water starts to evaporate as it is volatile when we start to heat we will also collect the water into another flask with the process of condensation. We will see a point will come when flask (1) will have no water left and whole of it is collected in another flask (3) and only NaI is left behind in (1).Thus we will see there are three flask now with seprated components of mixture:

(1) -> contains only NaI

(2) -> contains only n-octane

(3) -> contains only water

Thus now we can determine their mass separately .