Hydrolysis behavior of chlorides in water

Steps:

• NaCl dissociates into Na⁺ and Cl⁻ ions, neither hydrolyzes significantly, resulting in neutral pH.
• SiCl₄ reacts with water: SiCl₄ + 4H₂O → Si(OH)₄ + 4HCl, producing H⁺ ions for acidic pH.
• AlCl₃ undergoes hydrolysis: Al³⁺ + 3H₂O ⇌ Al(OH)₃ + 3H⁺, generating H⁺ ions for acidic pH.
• Universal indicator turns green for neutral (X), red for acidic (Y and Z).

Why A is correct:

• A states X neutral and Y/Z acidic, matching the lack of hydrolysis for NaCl versus acid-producing reactions for SiCl₄ and AlCl₃ per hydrolysis definitions.

Why the others are wrong:

• B claims all acidic; incorrect, as NaCl remains neutral without H⁺ production.
• C suggests all neutral; wrong, since SiCl₄ and AlCl₃ hydrolyze to form acids.
• D implies X acidic and Y/Z neutral; false, as only X avoids hydrolysis.

Final answer: A