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प्रश्न
Fill in the blank
A catalyst either ................or ............... the rate of a chemical change but itself remains ............... at the end of the reaction.
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उत्तर
A catalyst either increases or decreases the rate of a chemical change but itself remains unchanged at the end of the reaction.
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संबंधित प्रश्न
Balance the following equation :
Fe + H2O → Fe3O4 + H2
Choose the correct option from the bracket and explain the statement giving reason.
(Oxidation, displacement, electrolysis, reduction, zinc, copper, double displacement, decomposition)
To prevent rusting, a layer of ______ metal is applied on iron sheets.
What is the reaction called when oxidation and reduction take place simultaneously? Explain with one example.
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 |
Give an example of the following chemical change.
A reaction where colour change is noticed
State the type of reactions for the following represent and balance the ones that are not balanced.
NaOH + HCl → NaCl + H2O
Give a chemical test to distinguish between the following gases.
CO2 and SO2
Distinguish by heating the following in dry test tubs.
Zinc carbonate, Copper carbonate and lead carbonate.
Write your observation and a balanced equation in the case of the following substances being heated.
Ammonium dichromate.
Write your observation and a balanced equation in the case of the following substances being heated.
Copper nitrate.
Write your observation and a balanced equation in the case of the following substances being heated.
Copper carbonate.
Give a word equation for the following reaction.
Two gases which combine to give a solid.
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Calcium hydroxide.
A reaction between an acid and a base is called ______.
Silver metal can displace hydrogen gas from nitric acid.
Can a nickel spatula be used to stir copper sulphate solution? Justify your answer.
______ is a natural indicator.
Chemical changes are important in our day-to-day life. Give examples.
When milk is mixed with coffee decoction, the colour of milk and decoction changes due to ______.
