Final answer:
The balanced equation for the reaction when the two solutions are mixed is 2HCl + Na2CO3 => 2NaCl + H2O + CO2. This is a double displacement reaction, where two compounds exchange ions to form two new compounds.
Step-by-step explanation:
a. The balanced equation for the reaction that takes place when these two solutions are mixed is:
2HCl + Na2CO3 => 2NaCl + H2O + CO2
b. This reaction is known as a double displacement reaction, where two compounds exchange ions to form two new compounds.