Step-by-step Solution:

Step 1: Identify the reactants, products, and the reaction sequence.

1. Reactant P: The starting material is Aniline (C₆H₅NH₂).
2. Reaction 1 (Diazotization): Aniline (P) reacts with NaNO₂ and HCl at 0-5°C to form benzenediazonium chloride (C₆H₅N₂⁺Cl⁻). This is a standard diazotization reaction. C₆H₅NH₂ + NaNO₂ + 2HCl → C₆H₅N₂⁺Cl⁻ + NaCl + 2H₂O
3. Reaction 2 (Azo Coupling): The intermediate, benzenediazonium chloride, reacts with phenol (C₆H₅OH) in an alkaline medium (OH⁻). The diazonium cation acts as an electrophile and attacks the electron-rich phenol ring at the para-position (major product due to less steric hindrance). C₆H₅N₂⁺Cl⁻ + C₆H₅OH + OH⁻ → HO-C₆H₄-N=N-C₆H₅ + Cl⁻ + H₂O
4. Product Q: The final major product Q is p-hydroxyazobenzene, with the chemical formula C₁₂H₁₀N₂O.

Step 2: Calculate the molar masses of P and Q.

• Molar mass of P (Aniline, C₆H₅NH₂): $M_P = (6 × 12.0) + (7 × 1.0) + (1 × 14.0) = 72.0 + 7.0 + 14.0 = 93.0 g/mol$
• Molar mass of Q (p-hydroxyazobenzene, C₁₂H₁₀N₂O): $M_Q = (12 × 12.0) + (10 × 1.0) + (2 × 14.0) + (1 × 16.0) = 144.0 + 10.0 + 28.0 + 16.0 = 198.0 g/mol$

Step 3: Calculate the initial moles of reactant P.

• Volume of P = 9.3 mL
• Density of P = 1.00 g/mL
• Mass of P = Volume × Density = 9.3 mL × 1.00 g/mL = 9.3 g
• Moles of P ($n_P$) = Mass of P / Molar mass of P = 9.3 g / 93.0 g/mol = 0.1 mol

Step 4: Determine the theoretical yield of Q.

• The stoichiometry of the overall reaction from P to Q is 1:1. Therefore, 1 mole of aniline (P) theoretically produces 1 mole of p-hydroxyazobenzene (Q).
• Theoretical moles of Q ($n_Q, theoretical$) = Moles of P = 0.1 mol.
• Theoretical mass of Q = Theoretical moles of Q × Molar mass of Q Theoretical mass of Q = 0.1 mol × 198.0 g/mol = 19.8 g

Step 5: Calculate the actual amount of Q obtained.

• The overall yield of the reaction is given as 75% or 0.75.
• Actual mass of Q = Theoretical mass of Q × Yield Actual mass of Q = 19.8 g × 0.75 = 14.85 g

Conclusion: The amount of Q obtained from 9.3 mL of P is 14.85 g.

Answer Verification: The calculated answer is 14.85 g. The stored correct answer is 18.6. These values do not match. Let's analyze the discrepancy. To obtain 18.6 g of Q with a 75% yield, the theoretical yield would need to be 18.6 g / 0.75 = 24.8 g. This would require 24.8 g / 198.0 g/mol = 0.12525 mol of starting material P. This corresponds to 0.12525 mol × 93.0 g/mol = 11.65 g of P, not 9.3 g as given in the problem. It is highly likely there is a typo in the provided question data (e.g., the volume of P should have been ~11.6 mL). Based on the data given, the correct answer is 14.85 g.