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प्रश्न
A, B and C are all liquids. Liquid A has a comparatively low boiling point. On heating, liquid A vaporises completely without leaving behind any residue. Liquid A is being used increasingly as a fuel in motor vehicles either alone or by mixing with petrol. Liquid B has a very high boiling point. It also vaporises completely on heating, without leaving any residue. Liquid B is a conductor of electricity and used in making thermometers. Liquid C has a moderate boiling point. On heating, liquid C vaporises leaving behind a white solid D which is used in cooking vegetables. The condensation of vapours from C give a liquid E which turns anhydrous CuSO4 to blue.
(a) Which liquid could be an element ? Name this element.
(b) Which liquid could be a mixture ? Name this mixture.
(c) Which liquid could be a compound ? Name this compound.
(d) What could the solid D be ?
(e) What do you think is liquid E ?
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उत्तर
- Liquid B has a very high boiling point. It also vaporises on heating. It is a conductor of electricity and is used in making thermometers. So, B could be an element. Further, liquid B is mercury as mercury is a liquid metal, which expands on heating and is used extensively in thermometers.
- Liquid C has a moderate boiling point. It could be a mixture. It is a salt solution because when C is heated, it vaporises and leaves behind a white solid (salt), which is used in the process of cooking.
- Liquid A is used in motor vehicles as fuel, either alone or after mixing with petrol. It could be a compound because on heating, it does not leave any residue. It is alcohol as alcohol is being used in motor vehicles nowadays.
- Solid D is sodium chloride. It is also known as common salt and is added in food.
- Liquid E is water as, on heating, liquid C, which is a salt solution, leaves water vapours. On condensing these vapours, we obtain pure water. When water is mixed with anhydrous copper sulphate, we obtain a blue colour solution. This is because of the formation of hydrated copper sulphate solution.
\[\ce{CuSO4 + 5H2O →\underset{\text{hydrated copper sulphate}}{CuSO4.5H2O}}\]
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संबंधित प्रश्न
Differentiate between an atom and a molecule.
Name two processes which provide the best evidence for the motion of particles in matter.
Out of solids, liquids and gases, which one has :
- maximum movement of particles ?
- maximum interparticle attractions ?
- minimum spaces between particles ?
Which type of elements, metals or non-metals, show the property of brittleness ?
Fill in the following blanks with suitable words :
An element is made up of only one kind of ........
Name a non-metal :
- which is lustrous
- which is required for combustion
- whose one of the allotrophic forms is a good conductor of electricity. Name the allotrope.
- other than carbon which shows allotropy
- which is known to form the largest number of compounds
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.
What is the most common way of expressing the concentration of a solution ?
How much water should be added to 15 grams of salt to obtain 15 per cent salt solution ?
What will happen if a saturated solution is :
- heated
- cooled
State whether the following statement are true or false :
Alcohol can be separated from a mixture of alcohol and water by a separating funnel.
Which technique is used in a washing machine to squeeze out water from wet clothes while drying ?
Describe a method to separate a mixture of common salt and sand.
Describe the method of separating a mixture containing common salt, sand and ammonium chloride.
Describe the various steps involved in the separation of iodine, iron filings and salt from a mixture.
You are given a mixture of iodine in alcohol called tincture iodine. Which method will you use to recover both, iodine as well as alcohol, from this mixture ?
Justify your answer.
| Figure 1 | Figure 2 | Figure 3 |
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 |
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The arrangement of particles in three different phases of matter is shown above.
- Which state is represented by Fig. 1?
- In which state will the inter-particle attraction be maximum?
- Which one of them cannot be contained in an open vessel?
- Which one can take the shape of its container?
In Aerosol the dispersed phase is liquid and the dispersion medium is gas.
Gases change to liquid by the process of ______.
Define the term matter.
