Q1.
What will happen if we keep on adding more salt in a given amount of water?
Answer
At first every spoonful dissolves and the solution gets steadily more concentrated. Then a stage arrives when the added salt stops dissolving and settles at the bottom. From that moment the solution is saturated at that temperature, and no matter how much more salt you pour in, none of it will dissolve — the extra simply piles up as solid.
Why it happens: A fixed amount of water has a fixed capacity to keep solute particles apart and spread out. That capacity is used up gradually as you add salt. Once it is used up, the water cannot pull any more particles off the crystals, so the crystals stay whole and sink.
Tip: The solution above the settled salt is not weak — it is at its strongest possible for that temperature. Adding salt to a saturated solution changes the amount of solid at the bottom, not the strength of the liquid.