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प्रश्न
Fill in the following blanks with suitable words :
The gases of air can be separated by fractional distillation of liquid air because they have different..............
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उत्तर
The gases of air can be separated by fractional distillation of liquid air because they have different boiling points.
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संबंधित प्रश्न
What are molecules ?
Fill in the following blanks with suitable words :
Brass is an alloy which is considered a ..............
Fill in the following blanks with suitable words :
The elements which are sonorous are called ..........................
You are given two liquids, one a solution and the other a compound. How will you distinguish the solution from the compound ?
Name a metal which has no fixed shape.
Which of the following statements are true for pure substances ?
- pure substances contain only one kind of particles
- pure substances may be compounds or mixtures
- pure substances have the same composition throughout
- pure substances can be exemplified by all elements other than nickel
There are three substances X, Y and Z. The substance X does not have a fixed melting point or boiling point and it still shows the individual properties of its constituents. The substance Y is a pure substance which occurs in nature as such. The substance Y has a fixed melting point and boiling point but it cannot be broken down into simpler substances by any chemical means. The substance Z is also a pure substance whose properties are entirely different from those of its constituents. The substance Z can, however, be divided by electrolysis into two substances which belong to the same class of substances as Y.
- What type of substance could X be ? Name one substance like X.
- What type of substance could Y be ? Name one substance like Y.
- What type of substance could Z be ? Name one substance like Z.
- Which process involves absorption or release of an appreciable amount of energy : formation of substance X or formation of substance Z ?
- Name the three groups into which all the substances like Y are divided on the basis of their properties.
State whether the following statement is true or false :
Sponge is an example of solid sol.
Which of the following is a sol ?
Shaving cream, Milk, Fog, Soap solution, Hairspray
Classify the following into true solutions and colloidal solutions:
Ink, Salt solution, Starch solution, Blood, Sugar solution
Explain what happens when a beam of light is passed through a colloidal solution.
21.5 g of sodium chloride dissolves in 60 g of water at 25°C. Calculate the solubility of sodium chloride in water at that temperature.
Differentiate between a saturated and an unsaturated solution. How will you test whether a given solution is saturated or not ?
One of the following liquids will leave behind a residue on heating. This one is :
What difference in the property of two miscible liquids enables their separation by fractional distillation ?
How is water purified on a large scale at water works ? Explain with the help of a labelled diagram. Name the substance which is added to kill germs in the drinking water supply ?
Rusting of an article made up of iron is called
Non-metals are usually poor conductors of heat and electricity. They are non-lustrous, non-sonorous, non-malleable and are coloured.
Name a non-metal which exists as a liquid at room temperature.
The pressure of gases does not depend on the temperature of the gas and the volume it occupies.
Evaporation is always accompanied by ______ in temperature.
