A Level Chemistry OCR Practice Exam

What is a salt in terms of its chemical composition?

1. A compound formed solely from two metallic elements

2. A compound formed from an acid where a H+ ion is replaced by a metal ion or ammonium ion

3. A compound that has no ionic bonds

4. A compound that has equal numbers of positive and negative ions

The correct answer is: A compound formed from an acid where a H+ ion is replaced by a metal ion or ammonium ion

The correct answer, which defines a salt in terms of its chemical composition, highlights that a salt is indeed formed from an acid when a hydrogen ion (H+) is replaced by a metal ion or an ammonium ion. This process typically occurs during a neutralization reaction where an acid reacts with a base. Salts are generally classified as ionic compounds that consist of positive ions (cations) and negative ions (anions). In most cases, the cations derive from metal ions or ammonium ions, and the anions can come from the acid involved, creating a structure characterized by ionic bonding. This definition encapsulates the essence of salt formation, distinguishing it from other types of compounds. Other options miss the mark by various means: the first option incorrectly limits salts to being formed from only two metallic elements, ignoring the role of non-metals and ammonium. The third option wrongly states that salts do not contain ionic bonds, which fundamentally defines their structure. The fourth option, while discussing charges, does not specifically address the replacement of H+ ions nor the nature of salts as derived from acids. Hence, option B accurately captures the essence of what a salt is.