Hydrolysis reactions and pH indicators

Steps:

• NaCl dissolves in water to form neutral ions (Na⁺ and Cl⁻), no pH change in X.
• SiCl₄ reacts with water to hydrolyze, producing HCl (acidic) and SiO₂, lowering pH in Y.
• Z remains neutral water, pH 7.
• Universal indicator shows green for X and Z (neutral), red/orange for Y (acidic).

Why A is correct:

• A correctly identifies Y as acidic due to SiCl₄ hydrolysis forming HCl, per acid-base chemistry.

Why the others are wrong:

• B incorrectly suggests no color change in Y, ignoring hydrolysis.
• C wrongly claims X turns basic, but NaCl is neutral.
• D misstates Z as acidic without any solute.

Not enough information on exact statements in B, C, D, but assuming standard errors.

Final answer: A