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प्रश्न
Fill in the blanK
A .............is a substance which changes the rate of a chemical reaction without undergoing a chemical change.
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उत्तर
A catalyst is a substance which changes the rate of a chemical reaction without undergoing a chemical change.
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संबंधित प्रश्न
Define precipitation reaction.
TRUE \ FALSE
Copper can displace iron from iron sulphate.
What are chemical reactions?
Fill in the blank.
Melting of ice is a _______ change.
Give an example of a reaction where the following are involved:
Close contact
State the type of reactions for the following represent and balance the ones that are not balanced.
NaOH + HCl → NaCl + H2O
Name: Two nitrates that do not produce nitrogen dioxide on heating.
State the original colour of the following substance and colour of residue obtained after heating.
Copper carbonate
What do you observe when dilute sulphuric acid is added to the following:
Sodium Sulphide
Write your observation and a balanced equation in the case of the following substances being heated.
Copper carbonate.
Write your observation and a balanced equation in the case of the following substances being heated.
Zinc carbonate.
Represent the addition of dilute sulphuric acid to zinc by means of a chemical equation. State the function of the arrow between the reactants and products.
On heating which of the following substances i.e. copper carbonate, zinc carbonate, washing soda, copper sulphate, zinc nitrate, copper nitrate, lead nitrate, ammonium chloride and ammonium dichromate – relate to the reaction given below.
A coloured substance which leaves a black residue and evolves two gases one of which is acidic and coloured and the other neutral and colourless.
Complete the table given below.
| Addition of dil. H2SO4 to FeS | Odour of gas evolved |
Differentiate between the following:
Neutralization reaction and a precipitation reaction.
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Calcium hydroxide.
______ gas causes tears in our eyes while cutting onions.
NPK are the primary nutrients for plants.
Write word equations for two chemical reactions with the help of materials given in the box.
| Air, copper sulphate, iron, vinegar, iron oxide, carbon dioxide, iron sulphate, copper, lime water, water |
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?
