Question

The balanced net ionic equation for the reaction of calcium chloride and sodium phosphate contains which of the following terms?
(A) $3C{a^{2 + }}_{(aq)}$
(B) $P{O_4}{^{3 - }_{(aq)}}$
(C) $2C{a_3}{(P{O_4})_{2(s)}}$
(D) $6NaC{l_{(aq)}}$

Answer 1

Hint: The chemical formula of sodium phosphate and calcium chloride is $N{a_3}P{O_4}$ and $CaC{l_2}$. They react in a way that there is exchange of anions for the metals in the products.

Complete step by step answer:
We know that there are three sodium atoms in sodium phosphate and its molecular formula is $N{a_3}P{O_4}$. The molecular formula of calcium chloride is $CaC{l_2}$.
- So, both the salts react in a way that both the metals change their anions and give new salts. The unbalanced reaction of sodium phosphate and calcium chloride can be given as under.
     \[CaC{l_{2(aq)}} + N{a_3}P{O_{4(aq)}} \to C{a_3}{(P{O_4})_{2(s)}} + NaCl\]

- Now, we can see that the number of atoms present in the reactant’s side is not equal to the atoms present in the products’ side. So, in order to balance the chemical equation, we need to multiply the molecules in such a way that the number of particular atoms on the right hand side is equal to them in the left hand side in the equation.
- If we compare the calcium ions, then we can see that there is only one calcium ion present in the left hand side and there are three calcium ions in the right hand side. So, we need to multiply $CaC{l_2}$ by three in order to balance the calcium ions in the reaction.
- Same way, we also need to multiply $N{a_3}P{O_4}$ by 3, NaCl by 6 in order to balance the equation. So, we can write the balanced equation as
     \[3CaC{l_{2(aq)}} + 2N{a_3}P{O_4} \to C{a_3}{(P{O_4})_{2(s)}} + 6NaC{l_{(aq)}}\]

Now, we can see that 6NaCl is given in the options and it is present in the balanced equation. So, we can say that it is the correct answer.
So, the correct answer is “Option D”.

Note: You can try to balance an element in the reaction which is present in less numbers. This will make it easier for you to balance the equation. Always do a recheck whether the balanced equation we have proposed is correct or not to avoid errors.