Tag: chemistry

Questions Related to chemistry

The process of settling down of heavier, insoluble particles in an undisturbed mixture solution is called:

chemistry basic analytical techniques partition coefficients solvent extraction separation methods

  1. filtration

  2. centrifugation

  3. sedimentation

  4. decantation

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Correct Option: C
Explanation:

Sedimentation is the tendency for particles in suspension to settle out of the fluid in which they are entrained and come to rest against a barrier. This is due to their motion through the fluid in response to the forces acting on them: these forces can be due to gravity, centrifugal acceleration, or electromagnetism.

A very large quantity of mixture contains tiny particles of three different substances X, Y, and Z. They are of the same size, cubical in. shape and yellow in color. X particles are very heavy, insoluble, non-magnetic and contribute $50\, \%$ of the mixture. Y particles are very light, insoluble, non-magnetic and contribute $40\, \%$ of the mixture. And Z particles are actually iron pieces. Which of the following methods can separate X, Y, and Z in the fastest manner?

chemistry basic analytical techniques partition coefficients solvent extraction separation methods

  1. Winnowing-Magnetic separation

  2. Magnetic separation-Winnowing

  3. Sieving-Magnetic separation Filtration

  4. Handpicking - Sublimation-Sieving

Show answer
Correct Option: A
Explanation:

By Winnowing process heavy particles can be easily separated by blowing off the lighter particles with the help of air. Here Y is light and gets separated by winnowing. Then X and Z can be separated by the magnetic separation method because Z is magnetic.

The components of a mixture can be separated only by chemical means.

Write true or flase.

chemistry basic analytical techniques partition coefficients solvent extraction separation methods

  1. True

  2. False

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Correct Option: B
Explanation:

The components of a mixture can be separated by physical means.

Hence option-B is correct.

Heavy water is called as heavy because it:

chemistry basic analytical techniques partition coefficients solvent extraction separation methods

  1. is denser than common water

  2. is an oxide of deuterium

  3. has a heavy or bad test

  4. none of these

Show answer
Correct Option: B
Explanation:

Heavy water in which deuterium, a heavy isotope of hydrogen, takes the place of hydrogen. Heavy water has physical and chemical properties that are like those of ordinary water, but heavy water is 10 percent heavier and has higher freezing and boiling points.


Hence, option B is correct.

Some iron fillings are mixed with sand. We can separate them using magnetic separation method. This method is applicable only when:

chemistry basic analytical techniques partition coefficients solvent extraction separation methods

  1. magnetic substances are mixed up with non-magnetic substances

  2. magnetic substances are mixed up with magnetic substances

  3. magnetic substances are heated beyond their Curie temperatures

  4. two magnetic substances have equal melting points

Show answer
Correct Option: A
Explanation:

Magnetic separation is a process in which magnetically susceptible material is extracted from a mixture using a magnetic force. This separation technique can be useful in mining iron as it is attracted to a magnet.When magnetic substances are mixed with non-magnetic substances.

Wheat flour is separated from wheat bran by the method of:

chemistry basic analytical techniques partition coefficients solvent extraction separation methods

  1. handpicking

  2. sieving

  3. winnowing

  4. filtration

Show answer
Correct Option: B
Explanation:

The method of separation of particles from a mixture based on the difference in size of particles is known as sieving. It uses sieve plates for separation of coarse particles from finer particles. Wheat flour is separated from wheat bran by the method of sieving.

Choose the substance that is used as a filter.

chemistry basic analytical techniques partition coefficients solvent extraction separation methods

  1. Oil paper

  2. Silicon dioxide

  3. Unglazed porcelain

  4. Plastic

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Correct Option: C
Explanation:
Unglazed porcelain can be used as filters because it has small poses which filter some dirt.

The methods of separation used in municipal water works are:

chemistry basic analytical techniques partition coefficients solvent extraction separation methods

  1. loading, sedimentation, decantation and filtration

  2. sedimentation, filtration and distillation

  3. loading, decantation, sieving and distillation

  4. sedimentation, centrifugation and distillation

Show answer
Correct Option: A
Explanation:

The methods used include physical processes such as filtration, sedimentation, and distillation; biological processes such as slow sand filters or biologically active carbon; chemical processes such as flocculation and chlorination and the use of electromagnetic radiation such as ultraviolet light.

Which of the following solvents is used for separation of mixture of sand and sulphur?

chemistry basic analytical techniques partition coefficients solvent extraction separation methods

  1. Water

  2. Benzene

  3. Carbon di sulphide

  4. Ethyl alcohol

Show answer
Correct Option: C
Explanation:

The separation is carried out by using organic solvent carbon disulphide in which sulfur is soluble. Sand is insoluble and can be filtered out. The remaining solution is exposed to atmosphere from which carbon disulphide will gradually evaporate and sulfur is recovered back from the solution.

How is scrap-iron separated from other wastes in a scrap yard?

chemistry basic analytical techniques partition coefficients solvent extraction separation methods

  1. Sublimation

  2. Magnetic separation

  3. Handpicking

  4. Winnowing

Show answer
Correct Option: B
Explanation:

Waste materials supplied to factories contain a number of scrap metals including iron ore. so, in factories, scrap iron is separated from the heap of waste materials by using big electromagnets fitted to a crane.