HARD
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The boiling points of argon, nitrogen and oxygen are -1800C, -1960C and -1830C respectively. Which of these gases will distill first from their mixture in the air? Justify your answer. 
 

Important Questions on Matter: Elements, Compounds and Mixtures

EASY
A suitable method for the separation of pure naphthalene from sandy naphthalene is:
MEDIUM

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.

EASY

Given below are two statements:
Statement-I: Retardation factor Rf can be measured in meter/centimetre.

Statement-II: Rf value of a compound remains constant in all solvents.

Choose the most appropriate answer from the options given below:

EASY
On heating camphor in a porcelain dish it got mixed in air without melting. This phenomenon is known as
EASY
Which of the following contain five molecules of water of crystallisation?
MEDIUM

Using the provided information in the following paper chromatogram:

Question Image

The calculated Rf value of A is _____×10-1.

HARD

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.

MEDIUM

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, 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 cm3
The volume of water recovered=196 cm3
Mass of salt NaCl recovered= 68.8 g

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

  Sodium chloride Water
Molar mass (g mol-1) 58.44 18.02
Solubility in water (g/100 cm3) 35.9 -
Boiling point (°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?

EASY
You are given a mixture of iodine in alcohol called a tincture of iodine. Which method will you use to recover both, iodine as well as alcohol, from this mixture?
EASY

Distilled water cannot be used for which among the following purposes?

MEDIUM

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, 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 cm3
The volume of water recovered=196 cm3
Mass of salt NaCl recovered= 68.8 g

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

  Sodium chloride Water
Molar mass (g mol-1) 58.44 18.02
Solubility in water (g/100 cm3) 35.9 -
Boiling point (°C) 1413 100
Appearance White crystalline substance Colourless liquid

How can one obtain the water from the seawater?

MEDIUM

Which of the tubes in (a) and (b) will be more effective as a condenser in the distillation apparatus?

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EASY
Some substances can be obtained in a pure state from their solution by _____. (crystallisation/ filtration)
EASY

Ink is soluble in water. How can you get pure water from a mixture of ink and water?