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प्रश्न
The material which is added to water during purification process at the water works so as to disinfect it is :
विकल्प
potassium permanganate
betadine
chlorine
potash alum
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उत्तर
chlorine
Chlorine is added to water to purify it from the impurities such as bacteria.
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संबंधित प्रश्न
Liquids have definite shape and definite volume.
Give one difference between atoms and molecules.
Explain why air is used to inflate tyres.
Explain why, osmosis can be considered to be a special kind of diffusion. Classify the following into
(i) osmosis, and (ii) diffusion :
- swelling up of a raisin on keeping in water
- spreading of virus on sneezing
- earthworm dying on coming in contact with common salt
- shrinking of grapes kept in thick sugar syrup
- preserving of pickles in salt
- spreading of smell of cake being baked in the kitchen
- aquatic animals using oxygen dissolved in water during respiration
Which of the following are ‘pure substances’ ?
Ice, Milk, Iron, Hydrochloric acid, Calcium oxide, Mercury, Brick, Wood, Air
Define a compound. Give two points of evidence to show that sodium chloride is a compound.
Name a metal which forms amalgams.
Which one of the following is not a metalloid ?
On the basis of composition of matter, milk is considered to be :
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
What happens when the temperature of a saturated sugar solution is increased ?
What will happen if a saturated solution is :
- heated
- cooled
Define solubility of a substance. How does it vary with temperature ?
What do you understand by the statement " the solubility of copper sulphate in water at 20°C is 20.7 g" ?
Fill in the following blanks with suitable words :
Miscible liquids are separated by .....................
Describe a method for separating a mixture of iron filings and sulphur powder other than that by using a magnet.
Tincture of iodine is a mixture of two materials X and Y. The material Y has a property that its solid form can be converted directly into vapours on heating by a process called Z.
- What could X be ?
- What could Y be ?
- Name the process Z.
- Which process would you use to recover both the components X and Y from tincture of iodine ?
- Which process can be used to recover only component Y from tincture of iodine ?
What difference in the properties of common salt and sand would enable you to separate a mixture of these two substances ?
Why wires cannot be drawn from materials such as stone or wood?
A teabag placed in a cup of hot water will diffuse into the water.
