Stereoisomers

Step 1: Calculate the number of moles of NaCl. Molar mass of NaCl: Moles of NaCl in 5.85 g: Number of NaCl formula units: Step 2: Determine the number of unit cells. In a face-centered cubic (FCC) unit cell, 4 NaCl formula units are present per unit cell. Number of unit cells: Thus, and , so the correct answer is .

To solve this problem, we need to analyze two statements and determine which one is correct regarding entropy and Gibbs free energy at equilibrium.

1. Analyzing Statement I:
Statement I says, "The entropy of pure crystalline solid approaches zero as the temperature approaches absolute zero value." This is a correct statement based on the Third Law of Thermodynamics, which states that the entropy of a perfect crystalline solid approaches zero as the temperature approaches 0 K.

2. Analyzing Statement II:
Statement II says, "For a reaction at equilibrium, is zero." This is also correct. At equilibrium, the Gibbs free energy is zero because the system has reached a state where no net change occurs.

3. Final Answer:
Both statements I and II are correct. Therefore, the correct option is the one where both statements are correct.

Final Answer:
The correct option is (A) Both statements I and II are correct.

Step 1: Establish initial conditions and changes at equilibrium. Initial conditions set at 3 moles each for reactants with no ester or water. At equilibrium, formation of 2 moles of ester and water reduces reactants by 2 moles each.
Step 2: Calculate equilibrium concentrations and derive K. Given the reaction in a 1L vessel, equilibrium concentrations are directly equal to the moles at equilibrium:

To solve the problem, we need to identify the incorrect statement about adsorption.

1. Understanding Adsorption:
Adsorption is the process by which molecules or atoms adhere to a surface. There are various types of adsorption, such as physical and chemical adsorption, and they follow different thermodynamic principles.

2. Analyzing the Statements:

Physical adsorption is not specific in nature: This statement is correct. Physical adsorption is generally non-specific, meaning it can occur between a variety of adsorbents and adsorbates. It does not involve chemical bonds, just weak van der Waals forces.
In adsorption, , , and are negative: This statement is generally true for physical adsorption. For spontaneous adsorption, (Gibbs free energy) must be negative, and (enthalpy) is also negative due to exothermic nature. (entropy) is typically negative because the adsorbed molecules become more ordered on the surface.
acts as an auto catalyst in the hydrolysis of ethyl acetate: This is the incorrect statement. Ethanol ( ) is not an auto catalyst in the hydrolysis of ethyl acetate. In fact, the hydrolysis of ethyl acetate requires a catalyst like an acid or base, but not ethanol itself as an auto catalyst.
In Freundlich adsorption isotherm, , the value of is between 0 and 1: This statement is correct. In the Freundlich isotherm, is typically between 0 and 1, indicating that adsorption is not perfectly linear.

3. Final Answer:
The incorrect statement is the one related to ethanol ( ) acting as an auto catalyst in the hydrolysis of ethyl acetate.

Final Answer:
The correct option is (C) acts as auto catalyst in the hydrolysis of ethyl acetate.

Step 1: Determining the amount of acid neutralized by ammonia gas.

Moles of H SO taken:

Moles of NaOH used to neutralize excess H SO :

Since 2 moles of NaOH neutralize 1 mole of H SO , moles of unreacted H SO are:

Moles of H SO reacted with NH :

Moles of nitrogen in NH :

Step 2: Calculating the mass of nitrogen.

Mass of nitrogen:

Given that nitrogen is 46% of the organic compound:

Thus, the value of is 0.608 g.

To solve this problem, we need to analyze the reactions involving copper (Cu), zinc (Zn), and their interactions with nitric acid (HNO₃) in both dilute and concentrated forms.

1. Understanding the Reaction Process:
In the reaction between metals and acids, especially nitric acid, the type of acid (dilute or concentrated) can significantly affect the products.

Copper (Cu) and zinc (Zn) react with nitric acid to form different products based on whether the acid is dilute or concentrated. For example, dilute nitric acid typically produces nitrogen oxides (like N₂O or NO), whereas concentrated nitric acid typically produces nitrogen dioxide (NO₂).

2. Analyzing Each Reaction:

Option 1: The reaction is not correct. When copper reacts with dilute nitric acid, it typically forms Cu(NO₃)₂ and nitrogen oxides, but N₂O is not usually formed in this case, as copper generally forms Cu²⁺ ions in dilute nitric acid. This is the incorrect reaction.

Option 2: is correct. Zinc reacts with dilute nitric acid to form zinc nitrate and nitrogen oxide (N₂O), as expected.

Option 3: is correct. Copper reacts with concentrated nitric acid to form copper nitrate (Cu(NO₃)₂), nitrogen dioxide (NO₂), and water, which is a typical reaction.

Option 4: is correct. Zinc reacts with concentrated nitric acid to form zinc nitrate (Zn(NO₃)₂), nitrogen dioxide (NO₂), and water, which is a typical reaction as well.

3. Conclusion:
The reaction in Option A is not correct because the product N₂O is not typically formed when copper reacts with dilute nitric acid. Therefore, Option 1 is the correct answer.

Final Answer:
The correct answer is Option A.