When an ammonium salt dissolves in water, the resulting solution is acidic. Ammonium ions (NH\(_4\)\(^+\)) act as a weak acid when dissolved in water, donating a proton to water molecules and creating hydronium ions (H\(_3\)O\(^+\), which lowers the pH and makes the solution acidic.Consequently, option B is correct  since the pH of solution formed will be less than 7 not greater than 1 because greater than 1 can mean that it is alkaline.

Ammonium salts decompose when heated, typically releasing ammonia gas as one of the products. Ammonium salts break down into their constituent components, like ammonia and the corresponding acid, when exposed to heat. For example, ammonium chloride (NH\(_4\)Cl) decomposes into ammonia (NH\(_3\)) and hydrogen chloride (HCl) when heated.

Ammonium salts are generally very soluble in water; most simple ammonium salts readily dissolve in water, making them considered highly soluble. Which makes the statement incorrect.