Question

Write answer to the following question in your own words.

(a) How are the components of mixtures separated by simple methods ?
(b) Which elements ( metals and non-metals), compounds and mixtures do we use in our day-to-day life?
(c) In everyday life, where and for what purpose do we use centrifugation?
(d) Where are the methods of separation by distillation and by separating funnel used ? Why ?
(e) Which precaution will you take while using the methods of distillation and separation by separating funnel ?

Answer 1

a. The components of mixtures are separated by simple methods like:

Distillation: Distillataion and separating funnels are used in separation of liquid mixtures. Distillation is a method which is used for separating two miscible liquids. It is based on the difference in the boiling points of two liquids. Distillation can either be simple or fractional. Simple distillation can be used for liquids which have huge difference in their boiling points whereas fractional distillation is used in case of liquids which have close boiling points. Distillation can be used in the production of gasoline, distilled water, xylene, alcohol, paraffin, kerosene apart from separating mixtures.​

Separating funnels: Separation using separating funnels is used in case of immiscible liquids. It is based on the difference in the density of the two liquids. It can be used in separation of oil from water etc, two different types of immiscible oils etc.

Chromatography: It can be used to separate the coloured components of a mixture on the basis of the difference in the speeds of the components on chromatograph paper, when dissolved in the same solvent. The adsorbent paper acts as the stationary phase; it carries the components of the mixture on the paper. The mixture acts as the mobile phase and the components get separated. The component which moves slowly (i.e., the less-soluble component) appears as a spot on the lower side of the paper. The component which moves faster (i.e., the more-soluble component) appears as a dot on the higher side of the paper.

Centrifugation: Centrifugation is the process where a mixture is separated through spinning. It is used to separate skim milk from whole milk, water from your clothes, and blood cells from the blood plasma.

b. Examples of mixtures we use in our daily life are- lemon and water, sugar and milk, salt and water, cereal and milk, cement, air, etc.
Examples of compounds we use in our daily life are- salt (NaCl), sugar (C₁₂H₂₂O₁₁), baking powder (NaHCO₃), vinegar (CH₃COOH), ethanol etc.
Examples of elements we use in our daily life are- aluminium, copper, iron, silver, gold etc.


c. We use centrifugation for the following purposes in our daily lives:

• Drying of wet clothes in the spin tub of a washing machine
• Extraction of DNA for forensic and experimental purposes
• Separation of blood components in medical science
• Working of roller coasters in amusement park
• Removing water from wet lettuce in salad spinner

d. Distillataion and separating funnels are used in separation of liquid mixtures. Distillation is a method which is used for separating two miscible liquids. It is based on the difference in the boiling points of two liquids. Distillation can either be simple or fractional. Simple distillation can be used for liquids which have huge difference in their boiling points whereas fractional distillation is used in case of liquids which have close boiling points. Distillation can be used in the production of gasoline, distilled water, xylene, alcohol, paraffin, kerosene apart from separating mixtures.

Separation using separating funnels is used in case of immiscible liquids. It is based on the difference in the density of the two liquids. It can be used in separation of oil from water etc, two different types of immiscible oils etc.


e. Precautions to be used during disitillation:

• The apparatus should be set in a proper manner with all the components fitted well.
• Never heat the system that is totally closed from the outside atmosphere to prevent explosion.
• Add boiling chips to reduce bumping (rapid boiling causing the liquid to expel out of the container).
• Control the rate of heating so not to overheat to avoid bumping.

Precautions to be used while using separating funnel for separation:

• The funnel should be tightly fixed to the stand in an errect position.
• The liquid in the funnel should be left undisturbed to allow it to separate.
• The stopper should be removed carefully without disturbing the setup.