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प्रश्न
If you leave a piece of iron in the open for a few days, it acquires a film of brownish substance, called rust.
Can you change rust back into iron by some simple method?
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उत्तर
No, rusting is a chemical change and cannot be reversed.
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संबंधित प्रश्न
TRUE \ FALSE
The evolution of a gas during a chemical reaction is shown by an arrow pointing downwards. True or false ?
A chemical equation is a statement that describes a chemical change in terms of
Complete the statement by filling the gap using an appropriate term from the terms given in the bracket.
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An ______ is drawn in between the reactants and products while writing the equation for a chemical reaction.
Complete the table given below.
| Flame test for calcium chloride | Acid used for flame test |
State the following reaction represent oxidation or reduction.
\[\ce{H->H+}\]
_____ is the basic material to manufacture urea.
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Classify the following as physical or chemical properties
Most metal oxides form alkalis on interacting with water.
Classify each of the following, as a physical or a chemical change. Give reasons.
(a) Drying of a shirt in the sun.
(b) Rising of hot air over a radiator.
(c) Burning of kerosene in a lantern.
(d) Change the colour of black tea by adding lemon juice to it.
(e) Churning of milk cream to get butter.
Which is used as a catalyst during the process of hydrogenation of oils?
