Expressing Concentration Of Solutions

Answer (A) 0.1, 0.9

To calculate the mole fraction of a solute and solvent in a solution, we need to determine the number of moles of each component.

Given:

• Mass of NaOH = 4 g
• Mass of water = 16.2 g

Step 1: To find the number of moles of NaOH, we divide the given mass by the molar mass of NaOH. The molar mass of NaOH is:

Molar mass of NaOH = 22.99 g/mol (for Na) + 16.00 g/mol (for O) + 1.01 g/mol (for H) = 39.99 g/mol

Number of moles of NaOH = ≈ 0.1 mol

Step 2: To find the number of moles of water, we divide the given mass by the molar mass of water. The molar mass of water (H₂O) is:

Molar mass of H₂O = 1.01 g/mol (for H) + 1.01 g/mol (for H) + 16.00 g/mol (for O) = 18.02 g/mol

Number of moles of water = ≈ 0.9 mol

Step 3: Now, we can calculate the mole fraction of solute (NaOH) and solvent (water):

Therefore, the mole fraction of solute (NaOH) and solvent (water) in the given solution are approximately 0.1 and 0.9, respectively. So the correct option is 0.1, 0.9.

The percentage of alcohol in the solution is given by: The total mass of the solution is . Therefore: Thus, the correct answer is (A).

To calculate the mass percentage of the solute, we use the formula:
Where:
- Mass of solute = 4 g
- Mass of solvent (ethanol) = 46 g
- Mass of solution = Mass of solute + Mass of solvent = 4 g + 46 g = 50 g
Now, substituting these values:

Thus, the correct answer is 8\% (1).

Boiling points of organic compounds are affected by various factors such as molecular weight, intermolecular forces, and functional groups. The key factors here are: 1. Intermolecular hydrogen bonding: Compounds that can form hydrogen bonds generally have higher boiling points than those that cannot. 2. Electron-donating groups: Alkyl groups, which donate electron density, can slightly increase the boiling point. Let’s analyze the compounds: - CH -CH -CH -CH -NH : This is an amine with a primary amine group (-NH ). Primary amines can form strong hydrogen bonds, leading to a higher boiling point compared to the other compounds. - CH -CH -NH-CH -CH : This is a secondary amine. Although secondary amines can also form hydrogen bonds, they are less effective than primary amines because the nitrogen atom is less available for bonding. This results in a lower boiling point than the primary amine compound. - CH -CH -N(CH ) : This is a tertiary amine, which cannot form hydrogen bonds with itself (since the nitrogen atom is fully bonded to alkyl groups). Therefore, this compound will have the lowest boiling point among the three. Thus, the correct order of boiling points is: Primary amine > Secondary amine > Tertiary amine

We can use Raoult's Law to calculate the mole fraction of N in the solution. According to Raoult's Law, the mole fraction of a component in a solution is given by: Where: - is the mole fraction, - is the partial pressure of the component in the solution, - is the vapor pressure of the pure component. From the question: - The partial pressure of N is given as 7.698 bar. - The vapor pressure of pure N at 298K is 76.48K bar. Substituting the given values into the equation: Thus, the mole fraction of N in the solution is 0.1.

This reaction involves chlorination of toluene CH C H using chlorine Cl in the presence of iron(III) bromide (FeBr ) as a catalyst. This is an example of electrophilic aromatic substitution, where the chlorine atom will substitute a hydrogen atom on the benzene ring. In the case of toluene (methylbenzene), the methyl group (-CH ) is an electron-donating group and directs the incoming electrophile (chlorine) to the ortho and para positions relative to itself. However, since para substitution is more favored due to steric reasons, the chlorination will predominantly occur at the para position to the methyl group. Thus, the major product is 1-chloro-3-methylbenzene (since 1-chloro-3-methylbenzene is the para position for the methyl group).

Aspirin, a well-known pain-relieving medication, is also called acetylsalicylic acid. It is synthesized by the acetylation of salicylic acid, where the acetyl group -COCH is attached to the hydroxyl group of salicylic acid. - Methylsalicylate: This is a compound with a methyl ester group (-COOCH₃) and is commonly used as a rubefacient in topical ointments. - Ethyl salicylate: Similar to methylsalicylate, it is the ethyl ester of salicylic acid and is used in flavoring and fragrance products. - Acetylsalicylate: This is not the correct IUPAC name for aspirin; the correct name is acetylsalicylic acid. Thus, acetylsalicylic acid is the correct name for aspirin.

A Lewis acid is a species that can accept an electron pair. Among the given options: - AlCl₃ is a Lewis acid because aluminum in AlCl₃ has an incomplete octet and can accept an electron pair. - NH₃ is a Lewis base because it has a lone pair of electrons that can be donated. - OH⁻ is also a Lewis base because it has a lone pair of electrons to donate. - H₂O is a Lewis base because it also has lone pairs of electrons on the oxygen atom. Thus, the correct Lewis acid is AlCl₃.