Identify the correct statement for elemental sodium:

Question

Accepted Answer

Elemental sodium is a highly reactive metal, and its properties can be explained as follows:

1. **Option 4: It is easily oxidized.**  
   Sodium is a highly reactive alkali metal, which means it readily loses its outermost electron to form a positive ion. This makes it very susceptible to oxidation. When exposed to air, sodium quickly reacts with oxygen to form sodium oxide. This tendency to lose electrons and form compounds with oxygen or other elements is why sodium is considered to be easily oxidized. This property is a characteristic feature of alkali metals, including sodium.

2. **Option 1: It is a strong oxidizing agent.**  
   This statement is incorrect. Sodium is not an oxidizing agent; rather, it is a reducing agent. Oxidizing agents are substances that gain electrons in a chemical reaction, whereas reducing agents lose electrons. Since sodium readily loses electrons, it acts as a reducing agent, not an oxidizing agent.

3. **Option 2: It can be extracted by electrolysis of aqueous solution.**  
   This statement is incorrect. Sodium cannot be extracted from an aqueous solution by electrolysis because it reacts violently with water. Instead, sodium is typically extracted through the electrolysis of molten sodium chloride (NaCl) in a process known as the Downs process. In an aqueous solution, sodium would react with water to produce hydrogen gas and sodium hydroxide, making this method impractical for extraction.

4. **Option 3: It's density is lower than K.**  
   This statement is incorrect. Sodium (Na) actually has a higher density than potassium (K). The density of sodium is approximately 0.97 g/cm³, while the density of potassium is about 0.86 g/cm³. Therefore, sodium is denser than potassium, making this option incorrect.

In conclusion, Option 4 is the correct statement because it accurately describes sodium's tendency to be easily oxidized due to its high reactivity and propensity to lose electrons.