Question

Translate the following statement into chemical equation and balance it:
Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of Barium sulphate.
A. \[3BaC{{l}_{2(aq)}}+A{{l}_{2}}{{(S{{O}_{4}})}_{3(aq)}}\to 2AlC{{l}_{3(aq)}}+3BaS{{O}_{4(s)}}\]
B. \[BaC{{l}_{2(aq)}}+A{{l}_{2}}{{(S{{O}_{4}})}_{3(aq)}}\to AlC{{l}_{3(aq)}}+BaS{{O}_{4(s)}}\]
C. \[3BaCl+A{{l}_{2}}{{(S{{O}_{4}})}_{3}}\to 2AlC{{l}_{3}}+3BaS{{O}_{4}}\]
D. \[4BaC{{l}_{2(aq)}}+A{{l}_{2}}{{(S{{O}_{4}})}_{3(aq)}}\to 5AlC{{l}_{3(aq)}}+2BaS{{O}_{4(s)}}\]

Answer 1

Hint:
As given in the statement, we have Barium chloride and Aluminium sulphate as reactants, they react to give the products which are Aluminium chloride and Barium sulphate. We have to find the most stable oxidation state of all the ions and hence, find the formula for each compound. The balanced chemical reaction means that there is the same number of atoms of all the molecules at reactant side will be equal to that of the number of atoms of all the molecules at product side.

Complete answer:
We need to find out the ions which exist for the elements in the given compounds. Barium exists as \[B{{a}^{2+}}\] ion. Chloride exists as \[C{{l}^{-}}\] ion. Aluminium ion exists as \[A{{l}^{3+}}\] and Sulphate ions exist as \[S{{O}_{4}}^{2-}\] . This reaction is a kind of Double displacement reaction.
Now, we know what will happen in the reaction, the anion of barium sulphate will replace the anion of Aluminium chloride and vice versa. Thus, products will be \[AlC{{l}_{3}}\] and \[BaS{{O}_{4}}\].
Hence, we have got the products of the reaction and now we have to balance it and make the atoms of each element equal on both sides. On doing this we see that only the following reaction is balanced out of all the given option,
\[3BaC{{l}_{2(aq)}}+A{{l}_{2}}{{(S{{O}_{4}})}_{3(aq)}}\to 2AlC{{l}_{3(aq)}}+3BaS{{O}_{4(s)}}\]

So, the correct answer is “Option A”.

Note: A balanced equation is defined as an equation for a chemical reaction in which the number of atoms for each element involved in the reaction and the total charge is the same for both the reactants and the product side. In other words, the mass and the charge are balanced on both sides of the reaction.
A double-replacement reaction is a reaction in which the positive and negative ions of two ionic compounds exchange places to form two totally new compounds. The general form of a double-displacement reaction can be represented as: \[AB+CD\to AD+BC\]. These reactions are non-redox reactions as there is no change in the oxidation state of any species involved in the reaction.