A major factor considered in selecting a suitable method for preparing a simple salt is its

Correct answer: solubility in water.

Explanation: The method for preparing a simple salt depends mainly on whether the salt (and the starting materials) are soluble or insoluble in water. For example:

• Soluble salts (e.g., NaCl, KNO₃) are typically prepared by neutralization (acid + base), followed by evaporation/crystallization.
• Insoluble salts (e.g., AgCl, BaSO₄) are prepared by precipitation from two soluble solutions, then filtration and washing.

Why the others are not the key criterion:

• Crystalline form: This is an outcome of crystallization conditions, not the primary basis for choosing the preparation route.
• Melting point: Rarely dictates the aqueous preparation method.
• Reactivity with dilute acids: Relevant when selecting specific reactants (e.g., metal/oxide/carbonate + acid), but the overarching choice of method hinges on solubility (neutralization vs precipitation).