Final answer:
The reaction symbolized by AB + CD → AD + CB represents a double replacement reaction, where cations and anions of two ionic compounds exchange to form new compounds.
Step-by-step explanation:
The type of reaction symbolized by AB + CD → AD + CB is known as a double replacement reaction. In this type of chemical reaction, the positive and negative ions of two ionic compounds exchange places to form two new compounds. The ions A and C are positively-charged cations, while B and D are negatively-charged anions. Double replacement reactions typically occur between substances in aqueous solution, and they often result in the formation of a precipitate, a gas, or a molecular compound such as water.