Group 2 hydroxides increase in solubility and basicity down the group

Steps:

• Higher pH (13.6 for V) indicates stronger base from more soluble hydroxide; lower pH (9.4 for W) indicates weaker base from less soluble hydroxide.
• Group 2 hydroxides: solubility rises from Mg(OH)₂ (least soluble) to Ba(OH)₂ (most soluble).
• V must contain Ba (higher solubility, higher [OH⁻], higher pH); W must contain Mg (lower solubility, lower [OH⁻], lower pH).
• Options with hydroxides match if V is Ba(OH)₂ and W is Mg(OH)₂.

Why C is correct:

• Ba(OH)₂ is more soluble than Mg(OH)₂, producing higher [OH⁻] and pH 13.6 for V, while Mg(OH)₂ gives lower [OH⁻] and pH 9.4 for W, per solubility trends in Group 2.

Why the others are wrong:

• A: Both MgSO₄; same compound, violates different Group 2 elements; sulfates neutral, not basic.
• B: MgSO₄ and BaSO₄ insoluble/neutral; no high pH from OH⁻.
• D: Reverses assignment; Mg(OH)₂ would give high pH, Ba(OH)₂ low pH, contradicting data.

Final answer: C