Question

When sodium is treated with sufficient oxygen/air, the product obtained is: (a) \(\mathrm{NaO}_{2}\) (b) \(\mathrm{NaO}\) (c) \(\mathrm{Na}_{2} \mathrm{O}\) (d) \(\mathrm{Na}_{2} \mathrm{O}_{2}\)

Short answer

The product obtained is (d) \(\mathrm{Na}_2\mathrm{O}_2\).

Step-by-step solution

Understanding the Reactants

Determine the reactants involved in the chemical reaction: sodium (Na) and oxygen (O). Sodium is a reactive metal that readily interacts with oxygen present in air to form oxides.

Exploring the Oxides of Sodium

Investigate the possible oxides formed when sodium reacts with oxygen. Sodium can form different oxides based on the amount of oxygen available: sodium oxide \(\mathrm{Na}_2\mathrm{O}\), sodium peroxide \(\mathrm{Na}_2\mathrm{O}_2\), and sodium superoxide \(\mathrm{NaO}_2\).

Determining the Expected Product

Identify which oxide is commonly formed when sodium reacts with sufficient oxygen. Sodium reacts with excess oxygen to typically form sodium peroxide \(\mathrm{Na}_2\mathrm{O}_2\), rather than sodium oxide or sodium superoxide.

Selecting the Correct Chemical Equation

Based on knowledge of chemical reactions and behaviors of sodium in air, choose the correct reaction product that has a balanced equation. Sodium reacts with air to primarily form sodium peroxide: \( 2 \mathrm{Na} + \mathrm{O}_2 \rightarrow \mathrm{Na}_2 \mathrm{O}_2 \).

Key concepts

Chemical Reaction Mechanism

When discussing chemical reactions, it's crucial to understand the sequence of events at the molecular level that leads to the formation of a product. This sequence is known as the 1chemical reaction mechanism1. For sodium interacting with air, the process hinges on rearranging electrons between sodium and oxygen.

In this scenario, sodium (1Na1) initially loses an electron to become a positively charged ion. Oxygen (1O_21) acts as an electron acceptor. This electron transfer is what drives the reaction forward. The nature of this electron shift is crucial because sodium is very reactive, meaning it easily donates electrons. This quality makes it eager to interact with oxygen.

The chemical mechanism here specifically involves sodium atoms forming ionic bonds with oxygen atoms. The result of these complex interactions is the formation of different types of sodium oxides like 1Na_2O1, 1NaO_21, and most typically under excess oxygen conditions, 1Na_2O_21. Understanding these specific electron transfers is key to predicting and balancing the chemical equations involved in such reactions.

Sodium Peroxide Formation

Sodium peroxide is a fascinating compound that results from the reaction between sodium and oxygen in a specific ratio. Forming sodium peroxide, with the formula 1Na_2O_21, is quite typical when sodium metal is exposed to excess oxygen in the air. Generally, when two moles of sodium react with one mole of oxygen, sodium peroxide is the chief product. This simple reaction can be shown as:
\[ 2 \mathrm{Na} + \mathrm{O_2} \rightarrow \mathrm{Na_2O_2} \].

The peroxide ion consists of two oxygen atoms joined together by a single bond, which is known as a "peroxo" bond. This bond is what differentiates sodium peroxide from other oxides of sodium where oxygen atoms are not bonded to each other. To achieve this reaction, sodium needs to be in a highly reactive state, which is facilitated by its soft and shiny nature, making it easier to oxidize.

This process not only creates sodium peroxide but also highlights the diverse types of chemical bonds metal can form with oxygen under different conditions. Understanding sodium peroxide formation is vital to grasp the broader chemistry of alkali metals like sodium.

Oxidation States of Sodium

The oxidation state, or oxidation number, is an essential concept in chemistry that helps us understand the electron exchange during reactions. For sodium in its compounds, the oxidation state can tell us how many electrons it has lost during a reaction. In sodium's case, it's usually a +1 state because it loses one electron to achieve a more stable electronic configuration.

When sodium forms oxides, we observe different oxidation states of oxygen depending on the oxide type. For sodium peroxide (1Na_2O_21), the peroxide ion has an oxidation state of -1 for each oxygen atom, which is characteristic of peroxide bonds.

Understanding oxidation states is crucial as it aids in predicting the type of compounds formed during reactions, particularly those involving electron transfer like in the case of sodium and oxygen. Sodium's +1 oxidation state, combined with oxygen, not only helps form stable oxides but also makes it an interesting study in redox reactions. Recognizing these states helps students predict outcomes and write balanced chemical equations for complex interactions effortlessly.