Which reaction represents a chemical combination?
Which reaction represents a chemical combination?
The correct option is B CaO + H2O → Ca(OH)2
Explanation for Correct answer:
Combination reaction: A combination reaction is a type of chemical reaction in which two or more reactants combine together to form a single product.
Example of combination reaction:
Calcium oxide when added to water forms calcium hydroxide. In this two reactants combine to form a single product. Hence, option(b) is the correct answer.
Explanation for incorrect answer:
a. 2NaHCO3 → Na2CO3 + H2O+ CO2
In this reaction, a single reactant decomposes to form two or more products. Hence, it is not a combination reaction but it is a decomposition reaction.
Decomposition reaction: A decomposition reaction is a type of chemical reaction in which a reactant decomposes or breaks down to give one or more than one products.
c. CuSO4 + Fe → FeSO4 + Cu
In this reaction iron(Fe) is displacing copper(Cu) from the copper sulphate solution. Hence it is a displacement reaction.
Displacement reaction: A displacement reaction is a type of chemical reaction in which a more reactive metal displaces a less reactive metal from its salt solution.
d. AgNO3 + NaCl → AgCI + NaNO3
This is a double displacement reaction.
- Double displacement reaction: It is a type of chemical reaction in which there is an exchange of ions of the ionic compound between the reactants to form two new compounds.
Therefore, option(b) is correct option.
CaO + H2O → Ca(OH)2
Explanation for Correct answer:
Combination reaction: A combination reaction is a type of chemical reaction in which two or more reactants combine together to form a single product.
Example of combination reaction:
Calcium oxide when added to water forms calcium hydroxide. In this two reactants combine to form a single product. Hence, option(b) is the correct answer.
Explanation for incorrect answer:
a. 2NaHCO3 → Na2CO3 + H2O+ CO2
In this reaction, a single reactant decomposes to form two or more products. Hence, it is not a combination reaction but it is a decomposition reaction.
Decomposition reaction: A decomposition reaction is a type of chemical reaction in which a reactant decomposes or breaks down to give one or more than one products.
c. CuSO4 + Fe → FeSO4 + Cu
In this reaction iron(Fe) is displacing copper(Cu) from the copper sulphate solution. Hence it is a displacement reaction.
Displacement reaction: A displacement reaction is a type of chemical reaction in which a more reactive metal displaces a less reactive metal from its salt solution.
d. AgNO3 + NaCl → AgCI + NaNO3
This is a double displacement reaction.
- Double displacement reaction: It is a type of chemical reaction in which there is an exchange of ions of the ionic compound between the reactants to form two new compounds.
Therefore, option(b) is correct option.
