Question

If formaldehyde and \(\mathrm{KOH}\) are heated, then we get (a) methyl alcohol (b) acetylene (c) methane (d) ethyl formate

Short answer

The product is (a) methyl alcohol.

Step-by-step solution

Understand the Reaction

When formaldehyde (HCHO) is combined with a base such as potassium hydroxide ( ext{KOH}) and heated, a reaction known as the Cannizzaro reaction occurs. In this reaction, one molecule of formaldehyde is oxidized while another is reduced.

Identify the Products

In the Cannizzaro reaction of formaldehyde, the two products that are formed are methanol ( ext{CH}_3 ext{OH}) and formate ion ( ext{HCOO}^-). The methanol is a result of the reduction of formaldehyde.

Match the Product to the Options

The options provided include various compounds. Given that one of the products of this reaction is methanol (methyl alcohol), we need to identify which option corresponds to methanol. (a) methyl alcohol matches this description.

Key concepts

Understanding Formaldehyde

Formaldehyde is a simple yet incredibly important organic molecule. Its chemical formula is \( ext{HCHO}\). This compound is a colorless gas and is known for its pungent smell. Many students find it interesting to learn about because it is one of the simplest forms of aldehydes. Formaldehyde plays a significant role in organic chemistry reactions, including the Cannizzaro reaction.
Formaldehyde can act as both an oxidizing and reducing agent, which is unique among aldehydes. When you heat formaldehyde with an alkaline like potassium hydroxide, a Cannizzaro reaction occurs. In this process, two molecules of formaldehyde interact; one gets oxidized and the other reduced. Understanding this dual nature is crucial for mastering reactions like the Cannizzaro reaction. It's also used industrially as a precursor to many chemicals and materials. In summary, formaldehyde is a versatile and foundational chemical in both laboratory and industrial settings.

Role of Potassium Hydroxide (KOH)

Potassium hydroxide, commonly depicted as \( ext{KOH}\), is a strong base used in various chemical reactions. In the Cannizzaro reaction, it acts as a catalyst, empowering the aldehyde molecules to react with each other.
\( ext{KOH}\) breaks down in water to produce potassium ions \( ext{K}^+\) and hydroxide ions \( ext{OH}^-\). The hydroxide ions are particularly reactive and play a critical role in the reaction process. They attack the carbonyl carbon of formaldehyde, triggering the key steps of the Cannizzaro reaction.
The utility of \( ext{KOH}\) extends beyond the classroom as it is also used in everyday products, from soaps and batteries to food production. The mechanism by which \( ext{KOH}\) enables formaldehyde molecules to convert into methanol and formate ions is a splendid example of its effectiveness as a chemical agent.

Formation of Methanol

Methanol, or methyl alcohol, has a chemical formula of \( ext{CH}_3 ext{OH}\). It is one of the two products generated during the Cannizzaro reaction of formaldehyde.
As the reaction proceeds, one molecule of the formaldehyde is reduced, leading to the formation of methanol. This happens because the carbon in formaldehyde is reduced by accepting hydrogen atoms. Methanol is frequently used in various applications, ranging from solvents to antifreeze, and even as a fuel in some cases.
Its significance in studying the reaction is profound, as the transition in carbon's oxidation state highlights fundamental chemical transformation processes. The simple structure of methanol makes it an excellent subject of study for understanding alcohols, helping build a solid foundation for mastering organic chemistry.

Understanding the Formate Ion

The formate ion is a result of the oxidation process in the Cannizzaro reaction, where one of the formaldehyde molecules gives up electrons.
The chemical representation of the formate ion is \( ext{HCOO}^-\). It emerges when one molecule of formaldehyde is oxidized, becoming formic acid and then losing a proton to form the formate ion. This conversion underscores the dual nature of formaldehyde in the Cannizzaro reaction, acting as both a reducing and oxidizing agent.
Formate ions are important in various chemical contexts, often used industrially in dyeing processes or as preservatives. Understanding the behavior of formate ions in reactions can demystify concepts such as reaction mechanisms and oxidation states, providing valuable insights into the larger world of chemistry.