Answer:
1) Temperature
When salts like KNO3, NANO3 and KCl are added in water the test tube ecomes cold, which means the heat is being absorbed. Solubility usually increases with increase in temperature for such solutes.
On the other hand, when salts like Li2SO4 and Ce2(SO4)3 are dissolved in water, test tube turns warm which indicates the heat is released. In such cases the solubility of salt decreases with increase in temperature.
In some cases,the heat is neither absorbed nor releasedwhen dissolved in water. When salts like NaCl is added in water, the temperature remains the same, and hence temperature has minimal effect on solubility.
2) Pressure
The solubility of solid and liquids aren't affected by pressure but the solubility of gas in a liquid is directly propotional to the pressure of gas. This is also explained through Henry's Law. i.e.
m ∝ P or m = KP
where "m" is the amount of gas dissolved.
Hope that helps, it might be a little too detailed and lenthy, but it explains everything you asked.
