Tag: chemistry

Questions Related to chemistry

Which of the following is commonly used for removing the water layer from a system containing oil and water?

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

  1. Thermometer

  2. Separatory funnel

  3. Fiame spectrophotometer

  4. Burette

  5. Volumetric flask

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Correct Option: B
Explanation:

Water and oil are immiscible and they form two separate layer, oil have less density than water, so it floats on the water surface so, the water and oil layer can easily be separated by the separatory funnel.

Which statement explains why oxygen can be separated from nitrogen by the fractional distillation of liquid air?

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

  1. Oxygen is more dense than nitrogen

  2. Oxygen is more reactive than nitrogen

  3. The two elements have different boiling points

  4. The two gases are in different groups of the Periodic Table

Show answer
Correct Option: C
Explanation:

Fractional distillation is a process of separation of mixtures based on the difference in their boiling points.

so, oxygen and nitrogen can be separated by fractional distillation because they have different boiling points.

Which of the following processes enable pure water to be obtained from seawater?
I filtration
II distillation
III evaporation

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

  1. I and II only

  2. I and III only

  3. II and III only

  4. I,II and III

Show answer
Correct Option: C
Explanation:

Distillation and evaporation enables pure water to obtained from seawater,

both these process includes the evaporation of water and then condensing the water vapours to obtain pure form of water.

During distillation, some porcelain chips are added to the mixture being distilled to ______________.

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

  1. make the distilling flask more stable

  2. purify the mixture

  3. raise the temperature

  4. make the boiling smoother

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Correct Option: A
Explanation:

Procelain chips are added to the mixture for two reasons: to prevent the superheating of liquid and to make the distilling flask more stable.

Due to difference in degree of adsorption of gases by charcoal, a mixture of noble gases can be separated by adsorption on:

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

  1. burnt charcoal

  2. coconut charcoal

  3. powdered charcoal

  4. coke

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Correct Option: B
Explanation:

Due to difference in degree of adsorption of gases by charcoal, a mixture of noble gases can be separated by adsorption double walled tube containing coconut charcoal.

Which of the following statements are true with respect to the effect of solubility with temperature?

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

  1. Solubility of gas in liquid increases with temperature

  2. Solubility of gas in liquid decreases with temperature

  3. Solubility of solute in solution increases with temperature

  4. Solubility of solute in solution decreases with temperature

Show answer
Correct Option: B,C
Explanation:

Due to the increase in kinetic energy at higher temperature, the solvent milecules effectively break the solute molecules that are held together by intermolecular forces.

Therefore, solubility of solute in solution increases with temperature.
Also, the higher kinetic energy causes more motion in the gas molecules which break intermolecular bonds & escape from solution.
Therefore, solubility of gas decreases with temperature.

$20\ ml$ of a mixture of oxygen and ozone was heated till ozone is completely decomposed. The mixture on cooling was found to have a volume of $21\ ml$. The volume percentage of ozone in the initial gaseous mixture is

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

  1. $20\%$

  2. $7.5\%$

  3. $80\%$

  4. $30\%$

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Correct Option: B

The volume of water that would convert $10\ ml$ of decamolar $HCl$ solution to decamolar solutions is 

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

  1. $10^{3}\ ml$

  2. $10^{2}\ ml$

  3. $9.9\times 10^{3}\ ml$

  4. $1.2\ L$

Show answer
Correct Option: A
Explanation:
Milli moles of conc.HCl=milli moles of dil HCl
10×10=V×11010×10=V×110⇒V=1000ml⇒V=1000ml
Thus 990ml of water should be added to 10ml on conc.HCl to get decinormal solution.
Hence (a) is the correct answer.

Let the solubilities of AgCl in pure water, 0.01 M $CaCl _2$, 0.01 M NaCl & 0.04 M $AgNO _3$ be $S _1, S _2$ & S_3 , S_4$ respectively what is the correct order:

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

  1. $S _1 > S _2 > S _3 > S _4$

  2. $S _1 > S _2 =S _3 > S _4$

  3. $S _1 > S _3 > S _2 > S _4$

  4. $S _4 > S _2 > S _3 > S _1$

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Correct Option: A

An azeotropic mixture cannot be separated into its components by fractional distillation.

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

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

An azeotropic mixture cannot be separated into its components by fractional distillation because, when an azeotrope is boiled, the vapor has the same proportions of constituents as the unboiled mixture. The statement is true