Question

Which of the following is produced when magnesium reacts with hot concentrated \(\mathrm{H}_{2} \mathrm{SO}_{4} ?\) (a) \(\mathrm{H}_{2}\) (b) \(\mathrm{S}\) (c) \(\mathrm{MgO}\) (d) \(\mathrm{SO}_{2}\)

Short answer

(d) SO_2

Step-by-step solution

Understand the Reactants and Product Formation

Magnesium (Mg) is a reactive metal that, when reacted with hot concentrated sulfuric acid ( H_2SO_4}, can produce different compounds depending on the conditions. We are given options for the possible products of this reaction.

Write the Balanced Chemical Equation

Magnesium reacts with hot concentrated sulfuric acid to form magnesium sulfate (MgSO_4 ight) and, under these conditions, sulfur dioxide (SO_2) is also produced along with water.Thus, the equation for this reaction is:\[ Mg + 2 H_2SO_4 \rightarrow MgSO_4 + SO_2 + 2 H_2O \].

Analyze Possible Byproducts

Among the options given, (a) hydrogen gas (H_2) and (c) magnesium oxide (MgO) are not typically produced in this reaction with hot concentrated H_2SO_4}. Sulfur (S) could theoretically be reduced but not in significant amounts in this condition - more commonly, sulfur dioxide (SO_2) is a major reduction product with sulfuric acid.

Confirm the Correct Answer

From the balanced chemical equation, it is clear the primary produced gas is sulfur dioxide (SO_2). Therefore, the correct answer from the options provided is (d) SO_2.

Key concepts

Chemical Equation Balancing

Balancing chemical equations is like solving a puzzle. For any chemical reaction, the number of atoms for each element must be equal on both sides of the equation. This ensures that matter is conserved during the reaction. Let's talk about the reaction between magnesium (Mg) and sulfuric acid \( H_2SO_4 \).In this case, writing the unbalanced equation for the reaction, we have:\[ \text{Mg} + \text{H}_2\text{SO}_4 \rightarrow \text{MgSO}_4 + \text{SO}_2 + \text{H}_2\text{O} \]We need to make sure the number of each type of atom on the reactant side (left) matches the product side (right). Notice:

• 1 Mg on both sides
• 4 O in \( 2\ H_2SO_4 \rightarrow \) 4 O in \( \text{MgSO}_4 + 2 \text{H}_2\text{O} \)
• 2 S in \( 2\ H_2SO_4 \rightarrow \) 1 S in \( \text{MgSO}_4 \) and 1 S in \( \text{SO}_2 \)
• 4 H in \( 2\ H_2SO_4 \rightarrow \) 4 H in \( 2 \text{H}_2\text{O} \)

Make sure by balancing these elements, we follow the Law of Conservation of Mass, which states no atoms are lost or gained, just rearranged. Here, we ensured balance with the coefficients: 1 Mg, 2 \( H_2SO_4 \), producing 1 \( MgSO_4 \), 1 \( SO_2 \), and 2 \( H_2O \).

Products of Acid-Base Reactions

Acid-base reactions are fascinating because they often result in the formation of both a salt and water. This is exactly what we see when magnesium (Mg) reacts with sulfuric acid \( (\text{H}_2\text{SO}_4) \). In this case, the sulfuric acid donates \( 2\ \text{H}^+ \) ions, acting as an acid, while magnesium serves as the base. The reaction between Mg and \( \text{H}_2\text{SO}_4 \) produces magnesium sulfate \( (\text{MgSO}_4) \), which is a type of salt:\[ \text{Mg} + \text{H}_2\text{SO}_4 \rightarrow \text{MgSO}_4 + \text{H}_2 \]In typical conditions, such reactions might produce hydrogen gas (\( \text{H}_2 \)) as a byproduct. However, when sulfuric acid is hot and concentrated, \( \text{H}_2 \) is not the primary gas given off. These conditions alter the reaction, shifting the products to include sulfur dioxide \((\text{SO}_2)\) instead. In effect, reactions like this showcase the dynamic and adaptable interactions between acids and bases, with products heavily reliant on reaction conditions.

Sulfur Dioxide Production

Sulfur dioxide (\( \text{SO}_2 \)) is a significant product formed when magnesium reacts with hot concentrated sulfuric acid. Understanding its production helps illustrate how reaction conditions affect outcomes. In hot and concentrated conditions, sulfuric acid functions as both an oxidizing agent and an acid. The presence of such strong conditions leads sulfuric acid \((\text{H}_2\text{SO}_4)\) to reduce, producing \( \text{SO}_2 \) as a byproduct. Sulfur dioxide has a distinct scent, resembling that of a matchstick, and holds significance due to its role in atmospheric chemistry.

• It contributes to air pollution, such as acid rain.
• It's also used industrially to make sulfuric acid.

The chemistry of \( \text{SO}_2 \) production is nuanced by the fact that the sulfuric acid’s dual role in the reaction makes it versatile, resulting in different products under varying conditions. Recognizing the key factors like temperature and concentration allows chemists and students to predict and control the outcomes of reactions.