Problem 116 - A Complete Resource Book in Chemistry for JEE Main

Question

Regarding \(\mathrm{F}\) and \(\mathrm{Cl}\) which of the following statements is correct? 1\. \(\mathrm{Cl}\) can give up an electron more easily than \(\mathrm{F}^{-}\) 2\. \(\mathrm{Cl}\) is a better reducing agent than \(\mathrm{F}^{-}\) 3\. \(\mathrm{Cl}\) is smaller in size than \(\mathrm{F}\) 4\. \(\mathrm{F}^{-}\)can be oxidized more readily than \(\mathrm{Cl}^{-}\) (a) 1,2 and 4 (b) 1 only (c) 1 and 2 (d) 3 and 4

Step-by-Step Solution

Answer

The correct answer is (c) 1 and 2.

Step 1: Identify the Atomic and Ionic Properties

Consider the atomic properties of fluorine (\(\mathrm{F}\)) and chlorine (\(\mathrm{Cl}\)). Fluorine is smaller in size given they are in the same group, with \(\mathrm{F}\) at the top. Additionally, \(\mathrm{Cl}\) as an atom can lose an electron more easily compared to \(\mathrm{F}^{-}\) since \(\mathrm{F}^{-}\) is a negative ion, making it less likely to lose an extra electron.

Step 2: Analyze Reducing and Oxidizing Capabilities

Fluorine is a stronger oxidizing agent than chlorine because it has a higher electronegativity. Hence, \(\mathrm{Cl}\) is a better reducing agent than \(\mathrm{F}^{-}\). Conversely, \(\mathrm{F}^{-}\) is already reduced, making it more challenging to oxidize than \(\mathrm{Cl}^{-}\). Thus, statement 4 is incorrect.

Step 3: Evaluate the Size of Atoms

Since \(\mathrm{F}\) is above \(\mathrm{Cl}\) in the periodic table's halogen group, \(\mathrm{F}\) is smaller than \(\mathrm{Cl}\). Therefore, statement 3 is incorrect since \(\mathrm{Cl}\) is not smaller than \(\mathrm{F}\).

Step 4: Correct Statements Selection

From the analysis:- Statement 1, "\(\mathrm{Cl}\) can give up an electron more easily than \(\mathrm{F}^{-}\)," is true.- Statement 2, "\(\mathrm{Cl}\) is a better reducing agent than \(\mathrm{F}^{-}\)," is true.- Statements 3 and 4 are incorrect based on atomic size and redox properties.Therefore, the correct option is (c) 1 and 2.

Key Concepts

Halogen Group

The halogen group is a fascinating and important part of the periodic table. This group consists of five key elements: fluorine ( F), chlorine ( Cl), bromine ( Br), iodine ( I), and astatine ( At). They belong to Group 17 and are known for their high reactivity due to having seven valence electrons.
This configuration makes them eager to gain an extra electron to complete their outer shell. Among these elements, reactivity decreases as you move down the group, meaning that fluorine is the most reactive.

• Fluorine is the smallest and the most electronegative element, making it extremely effective in forming compounds by attracting electrons.
• Chlorine, while less reactive than fluorine, is still highly reactive and is commonly used in disinfectants, bleach, and other industrial applications.

Understanding the halogen group gives you insight into the chemical behavior and properties of these elements.

Atomic Properties

Atomic properties help us understand how atoms behave and interact with each other. Elements in the same group of the periodic table, like halogens, share some common atomic properties. For instance, as we move down the halogen group from fluorine to iodine, the atomic size increases.
This is because each element has an extra electron shell compared to the one above it.

• With an increase in atomic radius comes a decrease in electronegativity, meaning the ability to attract electrons lessens.
• Also, the ionization energy, or the energy required to remove an electron, decreases down the group.

These properties influence how reactive an element is and its capacity to act as an oxidizing or reducing agent. Chlorine, being below fluorine, has a larger size and lower ionization energy, making it easier for chlorine to lose an electron than fluorine.

Oxidizing and Reducing Agents

In chemistry, oxidizing and reducing agents are essential concepts in understanding reactions. An oxidizing agent gains electrons and gets reduced, while a reducing agent loses electrons and gets oxidized. Among halogens, fluorine is the strongest oxidizing agent due to its small size and high electronegativity.
This means it is highly effective at pulling electrons from other substances. Chlorine, while also being an oxidizing agent, is less strong compared to fluorine.

• This unique ability allows fluorine to easily form new compounds by attracting electrons from other atoms.
• Chlorine's position in the periodic table gives it the ability to reduce more easily than fluorine, as it can give up electrons relatively easier, identifying it as a better reducing agent compared to  F^-.

This balance of oxidizing and reducing capabilities of halogens plays a crucial role in redox reactions.

Electronegativity

Electronegativity is a key concept in understanding the bonding of elements. It is a measure of an atom's ability to attract and hold onto electrons within a bond. In the periodic table, electronegativity generally increases across a period from left to right and decreases down a group.
Fluorine tops the chart as the most electronegative element, which explains its high reactivity and its strength as an oxidizing agent.

• High electronegativity means that fluorine strongly attracts electrons towards itself, making it very reactive in chemical reactions.
• Chlorine, though less electronegative than fluorine, is still highly effective in forming bonds because of its strong attraction for electrons compared to many other elements.

Understanding electronegativity differences helps predict how elements will bond and react, playing a vital part in numerous chemical processes and compounds.