Problem 170 - A Complete Resource Book in Chemistry for JEE Main

Question

Select the correct statement(s): (a) \(\mathrm{Cl}_{2} \mathrm{O}\) and \(\mathrm{ClO}_{2}\) are used as bleaching agents and as germicides (b) \(\mathrm{ClO}_{2}\) is the anhydride of \(\mathrm{HClO}_{2}\) and \(\mathrm{HClO}_{3}\) (c) \(\mathrm{I}_{2} \mathrm{O}_{5}\) is used in the quantitative estimation of \(\mathrm{CO}\) (d) \(\mathrm{Cl}_{2} \mathrm{O}_{7}\) is anhydride of \(\mathrm{HClO}\)

Step-by-Step Solution

Answer

Statements (a) and (c) are correct.

Step 1: Analyze statement (a)

Statement (a) claims that \( \mathrm{Cl}_{2} \mathrm{O} \) and \( \mathrm{ClO}_{2} \) are used as bleaching agents and as germicides. \( \mathrm{Cl}_{2} \mathrm{O} \) (dichlorine monoxide) and \( \mathrm{ClO}_{2} \) (chlorine dioxide) are indeed used as bleaching agents and germicides. Therefore, statement (a) is correct.

Step 2: Analyze statement (b)

Statement (b) claims \( \mathrm{ClO}_{2} \) is the anhydride of \( \mathrm{HClO}_{2} \) and \( \mathrm{HClO}_{3} \). \( \mathrm{ClO}_{2} \) is not an anhydride of \( \mathrm{HClO}_{2} \) (chlorous acid) or \( \mathrm{HClO}_{3} \) (chloric acid). Therefore, statement (b) is incorrect.

Step 3: Analyze statement (c)

Statement (c) claims \( \mathrm{I}_{2} \mathrm{O}_{5} \) is used in quantitative estimation of \( \mathrm{CO} \). \( \mathrm{I}_{2} \mathrm{O}_{5} \) (iodine pentoxide) is indeed used for quantitative determination of carbon monoxide, as it oxidizes \( \mathrm{CO} \) to \( \mathrm{CO}_{2} \) while converting itself to iodine. Therefore, statement (c) is correct.

Step 4: Analyze statement (d)

Statement (d) claims \( \mathrm{Cl}_{2} \mathrm{O}_{7} \) is the anhydride of \( \mathrm{HClO} \). \( \mathrm{Cl}_{2} \mathrm{O}_{7} \) (dichlorine heptoxide) is actually the anhydride of \( \mathrm{HClO}_{4} \) (perchloric acid), not \( \mathrm{HClO} \) (hypochlorous acid). Therefore, statement (d) is incorrect.

Key Concepts

Oxides of Chlorine

Chlorine forms several oxides, each with different properties and uses. The two most common oxides are dichlorine monoxide (\( \mathrm{Cl}_{2} \mathrm{O} \)) and chlorine dioxide (\( \mathrm{ClO}_{2} \)). These compounds vary in their molecular structure and reactivity, but both are noted for their strong oxidizing properties. They are often used in industrial applications and water treatment processes due to these properties, making them effective at bleaching and disinfection. Understanding these substances helps in comprehending how chlorine can form multiple compounds, each with distinct functions and chemical behaviors. Exploring these oxides also illuminates their roles in various chemical and environmental contexts.

Bleaching Agents

Bleaching agents are substances that remove color from materials. They are widely used in paper and textile industries. Both \( \mathrm{Cl}_{2} \mathrm{O} \) and \( \mathrm{ClO}_{2} \) act as potent bleaching agents. These agents work by breaking down the chemical bonds of chromophores, which are the part of the molecules responsible for color.

• Effective in maintaining whiteness in laundry
• Used in disinfecting water supplies
• Involved in environmental management

However, due to their high reactivity, appropriate handling and use are crucial to prevent adverse effects on health and the environment. Understanding how and why they function helps in optimizing their use in different domains.

Anhydrides

Anhydrides are compounds formed by the removal of water from another compound, often acids. In the context of chlorine, \( \mathrm{ClO}_{2} \) is not considered an anhydride. Instead, \( \mathrm{Cl}_{2} \mathrm{O}_{7} \) is a significant chlorine-containing anhydride, serving as the anhydride of perchloric acid, \( \mathrm{HClO}_{4} \). Anhydrides are crucial in understanding how acids can convert to less hydrated states.

• Help in producing organic and inorganic acids
• Have unique reactivity patterns that influence synthesis reactions

Studying anhydrides prepares students to appreciate the intricate balance of hydration and dehydration in chemistry.

Chemical Reactions

Chlorine oxides are involved in various chemical reactions, displaying reactivity patterns that enable their diverse applications. For example, \( \mathrm{I}_{2} \mathrm{O}_{5} \), which is not a chlorine oxide, is used in reactions to estimate \( \mathrm{CO} \) by transforming it to \( \mathrm{CO}_{2} \), showcasing one type of oxidation reaction. Reactions involving chlorine oxides include oxidation of organic compounds and disinfection of bacteria and other pathogens. They are characterized by fast reaction rates due to their reactive nature.

• Oxidizes harmful gases to less toxic forms
• Reacts with water to form acids or release chlorine gas

By understanding these reactions, learners can grasp the practical applications of chlorine oxides in fields such as health, industry, and environmental management.