Question

When mercury boils with \(\mathrm{H}_{2} \mathrm{SO}_{4}\), then it formed and is liberated. (a) \(\mathrm{Hg}_{2} \mathrm{SO}_{4}, \mathrm{SO}_{2}\) (b) \(\mathrm{HgSO}_{4}, \mathrm{SO}_{2}\) (c) \(\mathrm{HgSO}_{4}, \mathrm{SO}_{3}\) (d) \(\mathrm{HgSO}_{4}, \mathrm{H}_{2}\)

Short answer

(b) \(\mathrm{HgSO}_{4}, \mathrm{SO}_{2}\)

Step-by-step solution

Identify the Reaction Components

When mercury (Hg) is reacted with sulfuric acid (\(\mathrm{H}2 \mathrm{SO}4\)), the primary reaction involves the formation of a mercury sulfate. We need to analyze which sulfate compound is formed during the reaction and what gas is liberated.

Understand the Reaction Concept

In this reaction, mercury typically forms mercury(II) sulfate (\(\mathrm{HgSO}4\)) when reacted with sulfuric acid. This is because mercury reacts with the \(\mathrm{SO}4^{2-}\) ion present in \(\mathrm{H}2 \mathrm{SO}4\) to result in \(\mathrm{HgSO}4\).

Determine the Gas Liberated

During the reaction of mercury with sulfuric acid, sulfur dioxide (\(\mathrm{SO}2\)) is commonly liberated as a gaseous product, which is typical for reactions involving hot sulfuric acid.

Review and Select Correct Option

We know that the reaction yields \(\mathrm{HgSO}4\) and \(\mathrm{SO}2\). Looking at the multiple choice options, option (b) which suggests \(\mathrm{HgSO}4\) and \(\mathrm{SO}2\) as products, matches the correct chemical processes.

Key concepts

Mercury reactions

Mercury is a fascinating element, known for its liquid state at room temperature and unique chemical behavior. In inorganic chemistry, mercury often reacts with a variety of substances including acids like sulfuric acid. When mercury comes into contact with sulfuric acid, it typically forms mercury(II) sulfate. This interaction is crucial in understanding how mercury behaves in the presence of acid, demonstrating its tendency to form stable compounds with sulfur-containing ions. Mercury's ability to engage in such reactions is partly due to its position in the periodic table which affords it a high oxidation state, making it reactive towards non-metals like sulfur.

Sulfuric acid reactions

Sulfuric acid (\(\mathrm{H}_{2}\mathrm{SO}_{4}\)) is a highly corrosive strong acid widely used in laboratory and industrial applications. It is known for its ability to react with metals, leading to interesting chemical transformations. When sulfuric acid reacts with mercury, it results in the formation of mercury sulfate (\(\mathrm{HgSO}_{4}\)) and the evolution of a gas. The acid provides sulfate ions (\(\mathrm{SO}_{4}^{2-}\)), which combine with mercury to form the compound. This process exemplifies the broader category of acid-metal reactions where the acid acts as an oxidizing agent, facilitating the formation of ionic compounds and the liberation of gases.

Gas evolution

Gas evolution is a common phenomenon in chemical reactions where gases are released as by-products. During the reaction between mercury and sulfuric acid, sulfur dioxide (\(\mathrm{SO}_{2}\)) is liberated as a gas. This happens because sulfuric acid is a strong oxidizing agent, especially when concentrated and heated, causing it to release sulfur dioxide upon reacting. This type of gaseous by-product is crucial in identifying the nature of the reaction, as it signifies the transformation of sulfur's oxidation state from within sulfuric acid to a lower state in sulfur dioxide. Understanding gas evolution is critical in predicting the outcomes and balancing chemical equations appropriately.

Chemical equations

Writing chemical equations helps us depict chemical reactions in a concise form. In the case of mercury and sulfuric acid, the reaction can be represented as follows: \[\mathrm{Hg} + \mathrm{H}_{2}\mathrm{SO}_{4} \rightarrow \mathrm{HgSO}_{4} + \mathrm{SO}_{2} + \mathrm{H}_{2}\mathrm{O}\] This equation succinctly shows the reactants and the products. It's an essential tool in chemistry for communicating what happens in a reaction. Balanced chemical equations ensure the law of conservation of mass is adhered to, indicating that the same number of each type of atom exists before and after the reaction.

Oxidation-reduction reactions

Oxidation-reduction reactions, or redox reactions, involve the transfer of electrons between chemical species. In the reaction between mercury and sulfuric acid, sulfur is reduced from its +6 oxidation state in sulfuric acid to a +4 state in sulfur dioxide. Here, sulfur acts as the oxidizing agent, while mercury is oxidized by donating electrons, typically going from a zero to a +2 oxidation state. These changes highlight how oxidation and reduction occur simultaneously, characterized by the gain and loss of electrons, which is central to understanding many inorganic chemical processes.