Question

The reaction,
$BaC{l_2}\, + \,{H_2}S{O_4}\, \to \,BaS{O_4}\, + \,2HCl$ is;
A. Combination reaction
B. Decomposition reaction
C. Displacement reaction
D. Double displacement reaction

Answer 1

In this reaction, when barium chloride is reacted with sulphuric acid we can observe that both the positively charged species or the cationic compounds and negatively charged species or anionic charged compounds are getting displaced and they switch to form new compound named barium sulphate and hydrochloric acid.

Complete step-by-step answer: In this reaction, we can observe that one-mole Barium chloride reacts with one mole of sulphuric-acid to give one-mole barium sulphate and a byproduct of two moles of hydrochloric acid.
$BaC{l_2}\, + \,{H_2}S{O_4}\, \to \,BaS{O_4}\, + \,2HCl$
We are able to observe that both the positively charged species i.e., $B{a^{2 + }}$ and ${H^ + }$ , and the negatively charged species i.e., $C{l^ - }$ and $S{O_4}^{2 - }$ are getting displaced to form new compound of barium sulphate and hydrochloric acid.
Therefore, we can observe a double displacement reaction.
In Double displacement reaction, the two ionic compounds i.e., cationic and anionic compounds are exchanged to form two new compounds. It is represented as follows,
$AB\, + \,CD\, \to \,AD\, + \,CB$
So, the correct option is D. Double displacement reaction.
Additional information: In Combination of reactions, the two or more elements/ compounds combine to form a single compound. In simpler words, the combination of two or more reactants to form one product is called a combination reaction. Since in this reaction the combination of reactants is taking place. It can be represented as follows,
$A\, + \,B\, \to \,C$
Or else,
$CaO\, + \,{H_2}O\, \to \,Ca{(OH)_2}$
For example,
$CaO\, + \,{H_2}O\, \to \,Ca{(OH)_2}$
In Decomposition reaction, the compounds break down into simpler substances. In simpler words, the compounds get decomposed to two or more compounds. It can be represented as follows,
$AB\, \to \,A\, + \,B$
In Displacement reaction, one of the elements or set of elements is displaced to another molecule. It can be represented as follows,
$AB\, + \,C\, \to \,AC\, + \,B$

Note: The double displacement reactions are classified into neutralization, precipitation and gas formation reactions:
Neutralization reactions: This reaction is a specific type of double displacement reaction. It is an acid-base reaction that occurs when an acid reacts with an equal amount of base. The acid-base reaction leads to the formation of salt (neutral) and water.
Precipitation reaction: Precipitation is the formation of a solid in a solution or within another solid during a chemical reaction. This process usually occurs when the concentration of dissolved ions in the solution exceeds the dissolving product.
Gas formation reaction: Some double substitution reactions produce a gaseous product that is then released from the solution and released into the air. When sodium sulfide and hydrochloric acid solutions are mixed, the reaction products are aqueous sodium chloride and hydrogen sulfide gas.