Question

${\mathrm{BaCl}}_2\left(\mathrm{aq}\right)+{\mathrm{Na}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)\to {\mathrm{BaSO}}_4\left(\mathrm{s}\right)+2\mathrm{NaCl}\left(\mathrm{aq}\right)$. The above reaction involves which type of reaction:

• A. Displacement
• B. Precipitation
• C. Combination
• D. Double displacement

Answer 1

Answer: (B), (D)

Double displacement

The correct options are (B) and (D):

Explanation for the correct answers:

Option (B): Precipitation:

1. This precipitation reaction is basically the chemical reaction in the aqueous solution in which the two ionic bonds will combine and this all will result in the formation of the insoluble salt.
2. The insoluble ionic solid which is formed after the ionic combination is knows as the precipitate which will not get dissolved in the aqueous solution.
3. So now basically, when a solution of Sodium sulphate is mixed with the solution of Barium chloride there will be a formation of the salt Barium sulphate which would be insoluble in nature and is a white precipitate so will remain in the solution.
4. Reaction: $\underset{\mathrm{Barium}\mathrm{chloride}}{{\mathrm{BaCl}}_2\left(\mathrm{aq}\right)}+\underset{\mathrm{Sodium}\mathrm{sulphate}}{{\mathrm{Na}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)}\to \underset{\mathrm{Barium}\mathrm{sulphate}}{{\mathrm{BaSO}}_4\left(\mathrm{s}\right)\downarrow }+\underset{\mathrm{Sodium}\mathrm{chloride}}{2\mathrm{NaCl}\left(\mathrm{aq}\right)}$

Option (D): Double displacement:

1. It is a chemical reaction in which the elements are basically exchanged between the two compounds .
2. Also when a solution of Sodium sulphate is mixed with the solution of Barium chloride then the double displacement reaction will take place in which the ions will get exchanged between the two compounds.
3. So in this reaction the sulphate ions from the Sodium sulphate are actually displaced by the Chloride ions and the Chloride ions in the Barium chloride are displaced by the Sulphate ions.
4. Reaction:$\underset{\mathrm{Barium}\mathrm{chloride}}{{\mathrm{BaCl}}_2\left(\mathrm{aq}\right)}+\underset{\mathrm{Sodium}\mathrm{sulphate}}{{\mathrm{Na}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)}\to \underset{\mathrm{Barium}\mathrm{sulphate}}{{\mathrm{BaSO}}_4\left(\mathrm{s}\right)}+\underset{\mathrm{Sodium}\mathrm{chloride}}{2\mathrm{NaCl}\left(\mathrm{aq}\right)}$

Explanation for the incorrect answers:

Option (A): Displacement:

1. This is a chemical redaction in which an element will replace the element of the compound.
2. The element which replaces the another element from the compound should have to be chemically more reactive one.
3. Example for the reaction: $\underset{\mathrm{Iron}}{\mathrm{Fe}\left(\mathrm{s}\right)}+\underset{\mathrm{Copper}\mathrm{sulphate}}{{\mathrm{CuSO}}_4\left(\mathrm{aq}\right)}\to \underset{\mathrm{Iron}\mathrm{sulphate}}{{\mathrm{FeSO}}_4\left(\mathrm{aq}\right)}+\underset{\mathrm{Copper}}{\mathrm{Cu}\left(\mathrm{s}\right)}$.
4. Hence, this option is incorrect.

Option (C): Combination:

1. A chemical reaction in which the two or more than two reactants will combine just to form a single product.
2. Example of this reaction: Burning of coal.
3. Equation: $\underset{\mathrm{Carbon}}{\mathrm{C}\left(\mathrm{s}\right)}+\underset{\mathrm{Oxygen}}{{\mathrm{O}}_2\left(\mathrm{g}\right)}\to \underset{\mathrm{Carbon}\mathrm{dioxide}}{{\mathrm{CO}}_2\left(\mathrm{g}\right)}$
4. Hence, this option is incorrect.

Therefore, the correct options are (B): Precipitation and (D) Double displacement.