Question

Complete the equation BaCI2(aq) + K2CO3(aq) —->

Answer 1

Step 1 - Understanding the reaction

This reaction is a precipitation reaction: one of the products formed by the reaction is water-insoluble. This is also called, for simplicity sake, a douple-replacement reaction.

In such reactions, the cations will exchange their places, i.e., they will combine with the other cation's anion:

`AB+CD\to AD+BC`

Step 2 - Solving the equation

Note Ba(2+) ion is ionic-bonded to Cl(-) anion, whereas K(+) ion is bonded to CO3(2-) anion. They will exchange places:

`\text{BaCl}_(2(aq))+K_2CO_(3(aq))\to\text{KCl}_((aq))+Ba_{}CO_(3(s))`

Note BaCO3 is a solid compound, because it is not soluble in water.

Step 3 - Balancing the reaction

To properly balance this reaction we have to multiply KCl by two:

`\text{BaCl}_(2(aq))+K_2CO_(3(aq))\to2\text{KCl}_((aq))+Ba_{}CO_(3(s))`