Usually you would call this a saturated solution. I hope this helps.
The following choices are all extensive properties, meaning they do not change with the amount of the substance. Although, 3 of the properties, namely, density, solubility and thermal conductivity are temperature-dependent. Since the problem did not mention of heating, let's assume Kenya just used it directly for her meal. Among the choices, I think shape would change. Once you place it in the meal, you can no longer pinpoint the salt because it's shape has been changed.
The answer is (3) pH 3 to pH 1. The pH is related to the concentration of H3O+ with the relationship: pH = -lg c(H+). So when concentration of H3O+ increase, the pH will decrease. And decrease 2 when when increase hundredfold. Because 100=10^2.