Question

Oxalic acid reacts with concentrated \(\mathrm{H}_{2} \mathrm{SO}_{4}\) to give a mixture of two gases. When this mixture is passed through caustic potash, one of the gases is absorbed. What is the product formed by the absorbed gas with caustic potash? (a) \(\mathrm{K}_{2} \mathrm{HCO}_{3}\) (b) \(\mathrm{K}_{2} \mathrm{CO}_{3}\) (c) \(\mathrm{KOH}\) (d) \(\mathrm{K}_{2} \mathrm{SO}_{4}\)

Short answer

The product formed is \(\text{K}_2\text{CO}_3\), which is option (b).

Step-by-step solution

Understand the reaction

The reaction between oxalic acid (\(\text{H}_2\text{C}_2\text{O}_4\)) and concentrated \(\text{H}_2\text{SO}_4\) produces carbon monoxide (\(\text{CO}\)) and carbon dioxide (\(\text{CO}_2\)) gases. This is due to the dehydration effect of concentrated sulfuric acid.

Identify the caustic potash action

Caustic potash, which is \(\text{KOH}\), can react with acidic gases. When the mixture of \(\text{CO}\) and \(\text{CO}_2\) is passed through caustic potash, only \(\text{CO}_2\) is absorbed because \(\text{CO}\) does not react with \(\text{KOH}\).

Determine the product of absorption

\(\text{CO}_2\), when absorbed in caustic potash (\(\text{KOH}\)), reacts to form potassium carbonate (\(\text{K}_2\text{CO}_3\)). The reaction is \(2\text{KOH} + \text{CO}_2 \rightarrow \text{K}_2\text{CO}_3 + \text{H}_2\text{O}\).

Choose the correct product

Based on the reaction in Step 3, the correct product formed by the absorbed gas (\(\text{CO}_2\)) with caustic potash (\(\text{KOH}\)) is potassium carbonate, which corresponds to option (b) \(\text{K}_2\text{CO}_3\).

Key concepts

Oxalic Acid

Oxalic acid, with the chemical formula \( ext{H}_2 ext{C}_2 ext{O}_4\), is an organic acid found in many plants and vegetables like rhubarb and spinach. It's important in chemistry due to its ability to donate protons, making it a diprotic acid. This means it can release two protons or hydrogen ions, which gives it reactivity with various substances.When combined with a strong dehydrating agent like sulfuric acid, oxalic acid undergoes a chemical reaction. In this process, it effectively loses water molecules. This results in the formation of gases such as carbon monoxide (\( ext{CO}\)) and carbon dioxide (\( ext{CO}_2\)). Understanding this reaction helps in comprehending its role in oxidation-reduction processes in chemistry.

Caustic Potash

Caustic potash is another name for potassium hydroxide, with the formula \( ext{KOH}\). It is a strong base highly capable of reacting with acids and gaseous compounds.This substance is utilized in a variety of applications. Its ability to absorb carbon dioxide makes it particularly valuable in processes like soap making and various chemical reactions. The absorption reaction between caustic potash and \( ext{CO}_2\) is important in understanding environmental and chemical processing.In practical scenarios, caustic potash works by neutralizing acids and absorbing gases. This results in the formation of compounds like potassium carbonate.

Carbon Dioxide Absorption

The ability of substances to absorb carbon dioxide is crucial in many chemical and environmental processes. In the context of chemistry, this is often done using a strong base like potassium hydroxide (caustic potash).When carbon dioxide gas (\( ext{CO}_2\)) comes in contact with potassium hydroxide, a chemical reaction occurs. This results in the formation of potassium carbonate (\( ext{K}_2 ext{CO}_3\)) and water:\[2 ext{KOH} + ext{CO}_2 \rightarrow ext{K}_2 ext{CO}_3 + ext{H}_2 ext{O}\]This reaction not only helps eliminate \( ext{CO}_2\) but also provides insights into carbon capture and storage methods. These methods are explored as solutions to address climate change.

Potassium Carbonate

Potassium carbonate (\( ext{K}_2 ext{CO}_3\)) is a white, water-soluble salt that appears after \( ext{CO}_2\) is absorbed by potassium hydroxide. This compound has a wide range of applications, for example, in the glass and ceramics industries. Its formation in chemical reactions provides insights into how gases can be controlled and used beneficially.Potassium carbonate forms when carbon dioxide interacts with the caustic nature of \( ext{KOH}\). This highlights its utility in controlling emissions and chemical manufacturing processes.

Sulfuric Acid Dehydration Effect

Sulfuric acid (\( ext{H}_2 ext{SO}_4\)) is a powerful dehydrating agent. When reacting with oxalic acid, it causes the removal of water, resulting in the formation of gas products like carbon monoxide and carbon dioxide.The dehydration effect is crucial in converting substances into desirable chemical forms. This process is not limited to oxalic acid but extends to other organic compounds that can undergo similar reactions.Understanding the behavior of sulfuric acid in these scenarios can help in learning how industrial processes are managed efficiently. It's particularly useful in the production of various chemicals by breaking them down into simpler gaseous products.