Q3 of 20 Page 143

Answer the following:

Classify the following into chemical combination, decomposition, displacement and double displacement reaction.


a) CaCO3 CaO + CO2↑


b) 2AgNO3 + Cu → Cu(NO3)2 + 2Ag ↓


c) 2SO2 + O2→ 2SO3↑


d) NaCl + AgNO3→ AgCl ↓ +NaNO3

a) CaCO3 + heat → CaO + CO2↑


In the given reaction, CaCO3 used sufficient energy in the form of heat and breaks up into calcium oxide (CaO) and carbon dioxide gas. Hence, this reaction is an example of decomposition reaction.


b) 2AgNO3 + Cu → Cu(NO3)2 + 2Ag ↓


In the given reaction, copper being more reactive displaces silver (Ag) from its compound (AgNO3) and form a new compound (Cu(NO3)2. Hence, this reaction is an example of displace reaction.


c) 2SO2 + O2→ 2SO3↑


In the given reaction, sulphur dioxide and oxygen (reactants) combined together to form a single product, i.e., SO3. Hence, this reaction is an example of combination reaction.


d) NaCl + AgNO3→ AgCl ↓ +NaNO3


In the given reaction, the exchange of ions of Na and Ag are taking place. Hence, this reaction is an example of double displacement reaction.


More from this chapter

All 20 →
3

Answer the following:

Group the following into physical change and chemical change.


Dissolving salt in H2O, Burning of a fuel,


Rusting of iron, melting of an ice cube.

 3

Answer the following:

Mention one example each for the different types of chemical reactions.

 3

Answer the following:

Write the advantages of writing a chemical equation using formulae and symbols.

 3

Answer the following:

During winter many plant leaves fallen on the earth do not cause pollution. But plastic papers which are thrown on the earth cause pollution. Name the types of chemical reaction associated with this observation.