CASE: Separating the components of seawater

Student A is given the task of designing an experiment to separate and collect the components of a sample of seawater, $\mathrm{NaCl}$ (aq). They are provided with standard laboratory apparatus. Following the experiment, the student recorded the following data for analysis.

The initial volume of seawater$=200.00 {\mathrm{cm}}^3$
The volume of water recovered$=196 {\mathrm{cm}}^3$
Mass of salt $\mathrm{NaCl}$ recovered$= 68.8 \mathrm{g}$

The student in their research for a laboratory report discovered the following facts.

	Sodium chloride	Water
Molar mass $(\mathrm{g} {\mathrm{mol}}^{-1})$	$58.44$	$18.02$
Solubility in water $(\mathrm{g}/100 {\mathrm{cm}}^3)$	$35.9$	-
Boiling point $(°\mathrm{C})$	$1413$	$100$
Appearance	White crystalline substance	Colourless liquid

All the water could not be collected during the separation process. Which of the following is not a reason for this?

Which of the following are NOT correct methods for separating the components of given mixtures?

I. The mixture of Iodine and sodium chloride by sublimation.

II. Plant pigments by chromatography.

III. Mixture of acetic acid and water by separating funnel.

IV. Oxygen, argon and nitrogen from air by fractional distillation.

At a refinery, petroleum is separated into several components by a process called fractional distillation using a fractionating column. Which of the following statement is incorrect about the process?
(I) Temperature decreases from the bottom to the top of the column
(II) At each level in the column only one compound is collected
(III) The fraction collecting at the top of the column is less volatile
(IV) The fraction with the highest boiling point condenses first and gets collected near the base of the fractionating column.

Give the principle and technique involved in the separation of pure water from impure water.