Tag: methods of separation

Questions Related to methods of separation

Fractional distillation is used to obtain the components of which of the following?
I air
II seawater
III muddy water
IV crude oil 

separation of components of mixtures methods of separation elements, compounds and mixtures chemistry

  1. I, II

  2. II, III

  3. I, IV

  4. I, III

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Correct Option: C
Explanation:

Fraction distillation is based upon the separation of components having very less boiling point difference, therefore components of crude oil and air can be separated using fractional distillation. In the air and in crude oil, the difference in boiling point of different components is very less. 

The vapour pressure of pure $A$ is $10$ torr and at the same temperature when $1\ g$ of $B$ is dissolved in $20\ g$ of $A$, its vapour pressure is reduced to $9.0$ torr. If the molecular mass of $A$ is $200\ amu$, then the molecular mass of $B$ is:

separation of components of mixtures methods of separation elements, compounds and mixtures chemistry

  1. $100\ amu$

  2. $90\ amu$

  3. $75\ amu$

  4. $120\ amu$

Show answer
Correct Option: B
Explanation:

So $0.1=\dfrac{moles \,\, of \,\, B}{moles of A+B}$

$0.1=\dfrac{1/m^2}{\dfrac{1}{m _2}+\dfrac{20}{200}}$
$0.1=\dfrac{1/m _2}{\dfrac{1}{m _2}+0.1}$
$\dfrac{0.1}{m _2}+0.01=\dfrac{1}{m _2}-\dfrac{0.1}{m _2}$
$0.01=\dfrac{0.9}{m _2}$
$m _2=\dfrac{0.9}{0.01}=90amu$

Which of the following technique is used for the separation of a mixture of a liquid and a gas?

separation of components of mixtures methods of separation elements, compounds and mixtures chemistry

  1. Boiling

  2. Sublimation

  3. Crystallization

  4. Fractional distillation

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Correct Option: A
Explanation:

The technique used for the separation of a mixture of a liquid and a gas is boiling. The gas is removed by application of heat.  With the increase in temperature, the solubility of gas decreases. The gas is collected separately

A mixture of hydrogen and chlorine can be seperated by passage through a porous pot.

separation of components of mixtures methods of separation elements, compounds and mixtures chemistry

  1. True

  2. False

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Correct Option: A
Explanation:

A mixture of hydrogen and chlorine can be separated by passage through a porous pot. This is because the diffusion of hydrogen more than that of chlorine in the porous pot. So, most of chlorine remains outside the pot.

${K} _{H}$ values for ${Ar} _{(g)}, {CO} _{2(g)}, {HCHO} _{(g)}$ and ${CH} _{4(g)}$ are $40.39,1.67,1.83\times {10}^{-5}$ and $0.413$ respectively. Arrange these gases in the order of their increasing solubility ?

separation of components of mixtures methods of separation elements, compounds and mixtures chemistry

  1. $HCHO< {CH} _{4}< {CO} _{2}< Ar$

  2. $HCHO< {CO} _{2}< {CH} _{4}< Ar$

  3. $Ar< {CO} _{2}< {CH} _{4}< HCHO$

  4. $Ar< {CH} _{4}< {CO} _{2}< HCHO$

Show answer
Correct Option: C
Explanation:

The solubility of the gas is inversely proportiona to the $K _H$ value. Here, $Ar$ gas has the highest $K _H$ value so least solubility and $HCHO$ gas has the least $K _H$ value so highest solubility.


So, the correct option is C.

Alcohol and water are best separated from one another by :

separation of components of mixtures methods of separation elements, compounds and mixtures chemistry

  1. distillation

  2. crystallization

  3. manual separation

  4. chromatography

  5. filtration

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Correct Option: A
Explanation:

Alcohol and water are best separated from one another by distillation. 


Alcohol and water are miscible but they have different boiling points.

If the difference in the boiling points of alcohol and water is less, fractional distillation can be used.

Hence the correct option is A.

Gases are separated from each other by:

separation of components of mixtures methods of separation elements, compounds and mixtures chemistry

  1. fractional evaporation

  2. fractional distillation

  3. fractional crystallisation

  4. fractional sublimation

Show answer
Correct Option: B
Explanation:
Gases can be separated by fractional distillation. Firstly, the mixture is cooled until it forms a liquid. This is followed by heating it. The gas with lower boiling point rises in the distillation column & is thus separated.