Raising the pH will increase the basicity of the solution. Since sulfate is a weak base, its molar solubility will decrease with increasing pH. This is because the base will be neutralized by the acid. When the solution is made more acidic, the solubility will increase. Hope this helps Solution Raising the pH will increase the basicity of the solution. Since sulfate is a weak base, its molar solubility will decrease with increasing pH. This is because the base will be neutralized by the acid. When the solution is made more acidic, the solubility will increase. Hope this helps.