Acertain substance has a solubility of 12 grams in 100 grams of water at 20°c. this means that the substance will begin to dissolve when 12 grams are present in solution when 12 grams of the substance are stirred into a beaker with 100 g of water, it will begin settling at the bottom when 12 g of the substance are dissolved in 100 grams of water, the solution will be dilute when 12 g of the substance are dissolved in 100 grams of water, the solution will be saturated

The solubility of a substance is defined as the maximum amount of substance that can be dissolved in 100g of solvent at a particular temperature.

As given that the substance has solubility of 12grams in 100grams of water at given temperature.

Thus

1) The substance will begin to dissolve when 12 grams are present in solution : False,  the substance will begin to dissolve once we have started adding solute to it.

2) When 12 grams of the substance are stirred into a beaker with 100 g of water, it will begin settling at the bottom : false, it will start to settle once there will be solute more than 12 grams

3) when 12 g of the substance are dissolved in 100 grams of water, the solution will be dilute : false, the solute will be dilute when the amount of solute is less than 12g [infact it is unsaturated]

4) when 12 g of the substance are dissolved in 100 grams of water, the solution will be saturated : true :  the solution will be called as saturated.