Diazonium Salts

Step 1: Understanding bond order.
Bond order can be determined using molecular orbital theory. For the B molecule, the molecular orbitals are filled as follows: - The bonding electrons in and cancel out, leaving a bond order of 0.

Step 2: Conclusion.
The bond order of B is 0, meaning there is no bond between the two boron atoms.

Step 1: Understanding the simple cubic lattice.
In a simple cubic lattice, the number of atoms per unit cell is 1. The formula to calculate the number of unit cells is:
Step 2: Calculating the volume of the unit cell.
The volume of the unit cell is given by: Where .

Step 3: Finding the number of unit cells.
Using the density formula: We calculate the number of unit cells in 100 g of metal. The final result is unit cells.

Step 4: Conclusion.
The correct answer is (D) .

Step 1: Identify the reaction type.
Benzene diazonium chloride reacts with ethanol in a reduction reaction.
Step 2: Reaction explanation.
Ethanol acts as a reducing agent and replaces the diazonium group by hydrogen, leading to the formation of benzene.
Step 3: Conclusion.
Therefore, benzene diazonium chloride on reaction with ethanol forms benzene.

Step 1: Understanding the reaction.
This reaction is a diazotization reaction where an aromatic amine (aniline) reacts with sodium nitrite (NaNO ) in the presence of copper to form a diazonium salt. This intermediate is then treated with a suitable electrophile (in this case, HBF ) to form the desired product. In this reaction, the product is nitrobenzene (C H NO ).
Step 2: Analyzing the options.
(A) C H NH : This is incorrect, as the reaction does not produce an amine.
(B) C H NO : This is the correct product, as nitrobenzene is obtained in this reaction.
(C) C H Cl: This is incorrect, as chlorobenzene is not formed in this reaction.
(D) C H F: This is incorrect, as fluorobenzene is not formed.
Step 3: Conclusion.
The correct product is C H NO , so the correct answer is (B).

Step 1: Formula for work done in compression.
For an ideal gas undergoing an isothermal compression, the work done is given by: Where is the pressure, and is the change in volume. The ideal gas law relates pressure and volume: For , , and changing from 5 m to 2.5 m , we calculate the work done. Substituting into the formula, we get the result:
Step 2: Conclusion.
The correct answer is (A) 497.5 kJ.

Step 1: Understanding the reaction.
The reaction of benzene diazonium chloride with aniline in an alkaline medium leads to the formation of an azo compound. The product is a yellow dye, commonly used in the textile industry.
Step 2: Analyzing the options.
(A) Yellow dye: This is correct. The product of this reaction is typically a yellow dye due to the formation of an azo compound.
(B) Blue dye: This is incorrect. The reaction does not produce a blue dye.
(C) Red dye: This is incorrect. The reaction typically produces a yellow dye, not a red one.
(D) Orange dye: This is incorrect. The reaction produces a yellow dye, not an orange dye.
Step 3: Conclusion.
The correct answer is (A) Yellow dye.

Step 1: Understanding the reaction mechanism.
The formation of p-hydroxyazobenzene from phenol and benzene diazonium chloride occurs via an electrophilic substitution mechanism. In this reaction, the electrophilic diazonium ion attacks the phenol ring at the para position, forming the final product.
Step 2: Analyzing the options.
(A) Nucleophilic substitution: This is incorrect. The reaction involves electrophilic substitution, not nucleophilic substitution.
(B) Electrophilic addition: This is incorrect, as the reaction is a substitution, not an addition.
(C) Nucleophilic addition: This is incorrect. The reaction is electrophilic, not nucleophilic.
(D) Electrophilic substitution: This is correct. The reaction proceeds through an electrophilic substitution mechanism, where the diazonium ion attacks the phenol ring.
Step 3: Conclusion.
The correct answer is (D) Electrophilic substitution.

Step 1: Define Balz–Schiemann reaction.
Balz–Schiemann reaction is used for preparation of aryl fluorides from aromatic diazonium salts.
Step 2: Reaction involved.
Aromatic diazonium tetrafluoroborate decomposes on heating to give aryl fluoride: Step 3: Eliminate incorrect options.
Ar–Cl and Ar–CN are formed by Sandmeyer reaction, not Balz–Schiemann reaction.
Step 4: Conclusion.
Hence, Ar–F is obtained from diazonium salts in Balz–Schiemann reaction.

Step 1: Concept
Halogens (except Fluorine) form various oxoacids due to their ability to expand their octet.
Step 2: Analysis
- **Chlorine (Cl):** Forms 4 oxoacids ( ). - **Bromine (Br):** Forms 3 oxoacids ( ). - **Iodine (I):** Forms 3 oxoacids ( ). - **Fluorine (F):** Forms only 1 oxoacid ( ) due to high electronegativity and lack of d-orbitals.
Step 3: Conclusion
Chlorine forms the maximum number of stable oxoacids.
Final Answer: (B)

Step 1: Formula
. Since is constant, .
Step 2: Calculate effective molality ( )
- (A) - (B) - (C) - (D)
Step 3: Conclusion
Wait, let's re-check the values. (B) is and (D) is . Among the given options, is the smallest. However, standard MHT-CET keys often cite m NaCl as the conceptual minimum if isn't correctly processed. Let's strictly follow the calculation: (D) is less than (B). *Correction:* Looking at the options provided, if (D) is , it is the minimum. If the question intended (B) as the answer, there might be a typo in the molality of (D). Based on the provided values, (D) is the minimum.
Final Answer: (D)