Question

When a solution of sodium sulphate and barium nitrate are mixed, sodium nitrate solution and solid barium sulphate is formed. Explain the nature of reaction?

Answer 1

Hint: Nature of chemical reaction changes depending upon the reactant used in the chemical reaction. Double displacement reaction is a type of chemical reaction which is defined as a reaction in which components from each reactant will be exchanged with each other to form a new compound.

Complete answer:
The medium used for double displacement reaction is generally water or aqueous medium because it will facilitate the generation of cations and anions. These ions proceed the reaction by switching their places with each other to form two new compounds.
Double displacement further categories as neutralization process, precipitation reaction and reaction which are accomplished with evolution of gases as their product.
In the precipitation reaction, when two reactants are reacted with each other they will form a compound with decreased solubility in the aqueous medium which makes a solid precipitate which tends to sink down in the reaction mixture.
Molecular formula of sodium sulphate is $\left( {N{a_2}S{O_4}} \right)$: It is composed of two ions - $N{a^ + }$ and $S{O_4}^{^{ - 2}}$.
Molecular formula of barium nitrate is $Ba{\left( {N{O_3}} \right)_2}$ : It is composed of two ions- $B{a^{ + 2}}$ and $N{O_3}^ - $
The balanced chemical reaction between sodium sulphate and barium nitrate is expressed as:
$N{a_2}S{O_{4\left( {aq} \right)}}$$ + $$Ba{\left( {N{O_3}} \right)_{2\left( {aq} \right)}}$$ \ to $$BaS{O_4}_{\left( s \right)} \downarrow $$ + $$2NaN{O_3}_{\left( {aq} \right)}$
From the above reaction, we see that sulphate ion from $\left( {N{a_2}S{O_4}} \right)$ replace the nitrate ion from $Ba{\left( {N{O_3}} \right)_2}$ to form a new compound barium sulphate $BaS{O_4}_{\left( s \right)} \downarrow $. Barium sulphate forms a precipitate in the solution. Hence, this reaction is a type of precipitation reaction which comes under double displacement reaction.

Note:
Barium sulphate is removed from the reaction mixture by filtration through suitable filter paper. Barium sulphate after purification is obtained as a white crystalline solid with no specific odour. Barium sulphate acts as a major source of barium.