Problem 4 - A Complete Resource Book in Chemistry for JEE Main

Question

Which of the following is a highly corrosive salt? (a) \(\mathrm{FeCl}_{2}\) (b) \(\mathrm{HgCl}_{2}\) (c) \(\mathrm{PbCl}_{2}\) (d) \(\mathrm{Hg}_{2} \mathrm{Cl}_{2}\)

Step-by-Step Solution

Answer

The highly corrosive salt is (b)  extrm{HgCl}_{2}.

Step 1: Identifying Keywords

Begin by understanding the question and determining essential keywords. Here, 'highly corrosive salt' is crucial to identifying a compound from the given options.

Step 2: Examining Each Compound

Review the properties of each compound presented in the options. Determine which of these compounds is known for being highly corrosive.

Step 3: Evaluating  extrm{FeCl}_{2}

 extrm{FeCl}_{2} is a salt formed from iron and chlorine. It is known for rusting when exposed to moisture but isn't recognized as highly corrosive, especially compared to some mercury salts.

Step 4: Evaluating  extrm{HgCl}_{2}

 extrm{HgCl}_{2}, also known as mercuric chloride, is highly toxic and corrosive. It's well known for these properties, particularly in comparison to other compounds listed.

Step 5: Evaluating  extrm{PbCl}_{2}

 extrm{PbCl}_{2} is lead(II) chloride, which is not highly corrosive. It is more often considered when discussing solubility issues rather than corrosivity.

Step 6: Evaluating  extrm{Hg}_{2}  extrm{Cl}_{2}

 extrm{Hg}_{2}  extrm{Cl}_{2} is less corrosive than  extrm{HgCl}_{2}. Also known as calomel, it is used in some medicinal applications and is not as corrosive as mercuric chloride.

Step 7: Conclusion

Based on the corrosive properties,  extrm{HgCl}_{2} is identified as the highly corrosive salt compared to other options.

Key Concepts

Corrosive salts

Corrosive salts are chemical compounds that can cause destruction or irreversible damage to other substances, particularly metals and organic tissues, through chemical reactions. These salts are often highly reactive, especially in the presence of water or moisture, and can lead to hazardous situations in various environments. Common examples include different metallic chlorides and other halides.

Key characteristics of corrosive salts include:

• High reactivity: They can interact aggressively with metals and other materials.
• Potential to release toxic substances: Many corrosive salts can liberate harmful gases or other toxic compounds upon reaction.
• Wide range of industrial and laboratory applications: Despite their dangers, corrosive salts are extensively used in industrial processes and scientific research because of their reactive properties.

Understanding these properties is crucial for safely handling these compounds and preventing potential hazards.

Inorganic chemistry

Inorganic chemistry is the branch of chemistry that deals with the study of inorganic compounds, which are those not primarily based on carbon-hydrogen bonds. It encompasses a wide array of substances, from salts and minerals to metals and simple molecules.

Some core areas within inorganic chemistry include:

• Coordination chemistry: This field studies compounds formed from a central metal atom bonded to surrounding molecules or ions.
• Metallurgy: This discipline involves the study and use of metals and their alloys, including extraction and processing techniques.
• Materials chemistry: Concerned with the properties and applications of materials such as ceramics, glasses, and polymers.

The study of inorganic chemistry helps us understand the chemical properties and behaviors of many everyday substances and plays a critical role in fields such as catalysis, electronics, and materials science.

Chemical properties

Chemical properties are characteristics of a substance that become evident during or after a chemical reaction, revealing how the substance interacts with other substances. These properties help in understanding the behavior and potential uses of a compound.

Key chemical properties include:

• Reactivity: This denotes how readily a substance undergoes chemical changes. Highly reactive substances, like corrosive salts, often require careful handling.
• Toxicity: This refers to the potential of a substance to cause harm to living organisms.
• pH level: This measures how acidic or basic a substance is, influencing how it reacts with other materials.

Knowing a compound’s chemical properties is vital in predicting its behavior in different environments and applications.

Mercuric chloride (HgCl_2)

Mercuric chloride, represented by the chemical formula \( \text{HgCl}_2 \), is an example of a highly corrosive salt known for its notable reactivity and toxicity. This compound consists of mercury and chlorine and is often utilized in various industrial and laboratory contexts, although its use is limited due to safety concerns.

Some key points about mercuric chloride include:

• Corrosivity: \( \text{HgCl}_2 \) is highly corrosive and can cause damage to both organic and inorganic materials.
• Toxic effects: The compound is extremely toxic if ingested, inhaled, or absorbed through the skin, making safety protocols essential during handling.
• Applications: Historically used in antisepsis and as a preservative, its applications are limited today due to its dangerous nature, with safer alternatives often preferred.

Despite the risks, understanding its properties allows for the careful use and control of mercuric chloride in specific environments where its unique capabilities may be required.