Ohio Assessment for Educators (OAE) Integrated Science (024) Practice Exam

Which of the following statements is true about sodium?

1. It is very stable in air

2. It reacts violently with water

3. It has a high melting point

4. It is a gas at room temperature

The correct answer is: It reacts violently with water

Sodium is known for its highly reactive nature, especially with water. When sodium comes into contact with water, it reacts vigorously, producing hydrogen gas and sodium hydroxide. This reaction can generate enough heat to ignite the hydrogen gas, leading to an explosive outcome. This characteristic is a significant aspect of sodium's behavior, establishing it as an alkali metal that does not exist freely in nature but is found in various compounds instead. The other statements are not accurate representations of sodium's properties. For instance, sodium is not stable in air; it can oxidize quickly, forming sodium oxide. Additionally, sodium has a relatively low melting point compared to metals, melting at about 98 degrees Celsius, so it does not qualify as having a high melting point. Finally, sodium is a solid at room temperature, not a gas. Understanding these characteristics helps to clarify why sodium's reactivity with water stands out.