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प्रश्न
Write true or false .
A black residue is formed when sugar is heated .
विकल्प
True
False
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उत्तर
True
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संबंधित प्रश्न
Define precipitation reaction.
Give a reason.
Wasp sting is treated with vinegar.
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A new substance is formed in a _______ change.
Name the type of chemical reaction shown by the following equation:
NaOH + HCl → NaCl + H2O
Complete the statement by filling the gaps using appropriate term from the terms given in the bracket.
(slow, coloured, arrow, fast, smell, milky, physical, product, chemical, reactant, covalent, ionic, octet, duplet, exchange, sharing, equality sign)
Rusting of iron is a ______ chemical change.
Match the pairs.
| a. | Photosynthesis | i. | Tendency to lose electrons |
| b. | Water | ii. | Reactant in combustion process |
| c. | Sodium chloride | iii. | Chemical change |
| d. | Dissolution of salt in water | iv. | Covalent bond |
| e. | Carbon | v. | Ionic bond |
| f. | Fluorine | vi. | Physical change |
| g. | Magnesium | vii. | Tendency to form anion |
When hydrogen burns in oxygen, water is formed; when electricity is passed through water, hydrogen and oxygen are given out. Name the type of chemical change involved in the two cases.
What do you observe? When
Water is added to the quick lime.
Complete and balance the following reaction:
\[\ce{Pb(NO3)2 ->[\Delta]}\]
Distinguish by dilute sulphuric acid.
Sodium sulphide and sodium sulphite?
Select the correct answer for the following options:
The black residue obtained on heating copper carbonate.
Select the correct answer for the following options:
The pale blue precipitated obtained when copper [II] sulphate reacts with sodium hydroxide.
State the following reaction represent oxidation or reduction.
\[\ce{Ag->Ag+}\]
Assertion: The formation of iron oxide from iron is a chemical change.
Reason: For the rust to form from iron, it must be exposed to air and water.
Burning of paper is the best example of ______ change.
______ is a natural indicator.
Melting of wax is a change where a solid changes to liquid state. Give one more such change which you observe in your surroundings
Galvanization is a process in which ______ is coated as a layer of iron.
The chemical formula of rust is ______.
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