Problem 62 - 43 Years JEE ADVANCED (1978-2020) + JEE MAIN Chapterwise & Topicwise Solved Papers Chemistry

Question

Match the following, choosing one item from column \(\mathbf{X}\) and the appropriate item from column \(\mathbf{Y}\). [1983 - 2 Marks] \(\mathbf{X}\) \(\mathbf{Y}\) (i) Haber (a) Activation energy (ii) Graham (b) Diffusion of gases (iii) Arrhenius (c) Octet rule (iv) Lewis (d) Ammonia synthesis

Step-by-Step Solution

Answer

(i) Haber - (d), (ii) Graham - (b), (iii) Arrhenius - (a), (iv) Lewis - (c).

Step 1: Identify Key Concepts in Column X

Read through each item in Column X to understand what each represents. Recognize that (i) Haber is associated with ammonia synthesis, (ii) Graham is known for the laws of diffusion of gases, (iii) Arrhenius is related to activation energy, and (iv) Lewis is linked to the octet rule.

Step 2: Match Haber from Column X to Column Y

Identify what the Haber process is known for. The Haber process is a chemical procedure used for synthesizing ammonia. So, (i) Haber from Column X matches with (d) Ammonia synthesis in Column Y.

Step 3: Match Graham from Column X to Column Y

Identify what Graham is known for. Thomas Graham formulated Graham's law, which describes the diffusion of gases. So, (ii) Graham from Column X matches with (b) Diffusion of gases in Column Y.

Step 4: Match Arrhenius from Column X to Column Y

Identify what Arrhenius is known for. Arrhenius developed a theory to explain the relationship between temperature and reaction speed, which involves activation energy. So, (iii) Arrhenius from Column X matches with (a) Activation energy in Column Y.

Step 5: Match Lewis from Column X to Column Y

Identify what Lewis is known for. Gilbert N. Lewis introduced the concept of the octet rule in chemical bonding. So, (iv) Lewis from Column X matches with (c) Octet rule in Column Y.

Key Concepts

Haber Process

The Haber Process, named after Fritz Haber, is fundamental in chemistry for synthesizing ammonia from nitrogen and hydrogen gases. This process is carried out under high pressure and temperature, typically around 200 atmospheres and 450 degrees Celsius. A metal catalyst, often iron, is used to speed up the reaction.
The importance of the Haber Process cannot be overstated, as ammonia is a crucial component in fertilizers, which contributes significantly to food production worldwide.

• Ammonia (NH₃) acts as a building block for various compounds, including urea.
• This process helps fix atmospheric nitrogen, making it usable for plants.
• It revolutionized agriculture by enhancing crop yields sustainably.

However, it requires considerable energy input, affecting its sustainability. Innovations are ongoing to make it more energy-efficient and environmentally friendly.

Graham's Law

Graham's Law is key to understanding the behavior of gases, especially their diffusion. Formulated by Thomas Graham in the 19th century, it states that the rate of effusion (or diffusion) of a gas is inversely proportional to the square root of its molar mass. This can be mathematically represented as:
\[\frac{{r_1}}{{r_2}} = \sqrt{ \frac{{M_2}}{{M_1}}}\]where \( r_1 \) and \( r_2 \) are the rates of diffusion of gases 1 and 2 respectively, and \( M_1 \) and \( M_2 \) their molar masses.

• Heavier gases diffuse more slowly than lighter ones due to their higher molar mass.
• This principle is used in separating isotopes and in respiratory functions in biology.

Graham's Law is foundational for students in predicting and explaining gas behaviors in various conditions, whether a lab setting or natural environments.

Arrhenius Equation

The Arrhenius Equation provides meaningful insight into chemical kinetics, demonstrating how temperature influences reaction rates. Developed by Svante Arrhenius, the equation is expressed as:
\[k = Ae^{-\frac{E_a}{RT}}\]where \( k \) is the rate constant, \( A \) is the pre-exponential factor, \( E_a \) is the activation energy, \( R \) is the universal gas constant, and \( T \) is the temperature in Kelvin.

• It emphasizes that higher temperatures increase the average kinetic energy of molecules, leading to more collisions that surpass activation energy.
• This equation aids in calculating the temperature dependence of reaction rates.
• Helps in understanding why certain reactions need specific temperatures to proceed efficiently.

For students, grasping this equation is pivotal in mastering topics like catalysis, enzyme activity, and other temperature-related phenomena in chemistry.

Octet Rule

The Octet Rule is a fundamental concept in chemistry that helps explain the stability of atoms in molecules. Introduced by Gilbert N. Lewis, the rule states that atoms tend to form bonds in such a way that they surround themselves with eight valence electrons, emulating the electron configuration of noble gases.
This rule applies mainly to the representative elements, especially in covalent bonding scenarios.

• For example, oxygen typically forms two bonds to achieve a complete octet.
• Carbon, with four valence electrons, forms four bonds in most of its stable compounds.

Though very useful for basic chemistry, there are exceptions. Some elements like hydrogen, helium, and those in the d-block can deviate.
Understanding the Octet Rule is key for predicting bonding patterns and the geometry of molecules, aiding significantly in visualizing and solving chemical equations.