(a) What is chromatography ? For which type of mixture is it used ?

(b) What are the advantages of chromatography ?

(c) Give two applications of chromatography.

Draw a well-labelled diagram to separate kerosene oil from water.

State the principles involved in the following methods used to separate the components of mixtures.

(a) Solvent extraction

(b) Gravity separation

(c) Fractional crystallisation

(d) Fractional distillation

Also give one example of a mixture separated by employing the above methods.

In a classroom demonstration, a chemistry teacher presented a mixture of three substances : iron filings (component A), common salt (component B) and sulphur powder (component C) in order to teach students about the separation of mixtures. He then asked the students to observe the steps carefully :

• When a magnet was brought near the mixture, one of the components was quickly separated.
• Water was then added to the remaining mixture. One of the substances dissolved, while the other did not.
• The insoluble component from the solution was separated through filtration.

Answer the following questions :

(a) What kind of solid-solid mixture was brought by the teacher ? Justify your answer.

(b) What was the observation when a magnet was brought near the mixture ? Why ?

(c) Which component remained insoluble and was collected on the filter paper ? Name the term used for the substance left on the filter paper.

(d) Can the component that dissolved in water be recovered from its solution ? How ?

(e) Give two examples of mixtures which you use in your daily life.