A student , determined the solubility of four substabces ,potassium nitrate ,sodium , sodim choride ,potassium choride and ammonium choride in a water at five different temperatures of `10^(@)C, 20^(@(C 40^(@)C,60^(@) C` and `80^(@)C` and obtained the following data :

(a) what mass of potassium nitrate woulds be needed to make a satured solution of potassium nitrate in 50 grams of water at `40^(@)C`? (b) what would be observed if a saturated solution of potassium choride at `80^(@)C` is left to cool to the room temperature ?
( c) what is the solubilty of each salt at `20^(@)`C ? which salt has the highest solubility at this temperature ?
(d) what is the effect of change of temperature on the solbubility of a salt as shown by the above date?

Explanation

(a) The solubilty of potassium nitrue at `40^(@)C` is 62 grams (see the given table ) . ,this means that 62 grams of potassium nitrate is needed to make a saturd soution of potassium mitrate niture in 100 grams of potassium nitrate which is `(62)/(2)=31` grams of potassium nitrate .
(b) when a saturated solution of potassium choride at `80^(@)`C is left the solution (because the solubitity decreases on cooling ).
( c) the solubility of various salts at `20^(@)`C potassium nitrate 32 g , sodium choride 36, potassium choride 35 , And Ammonium choride 37 g . Ammonium choride has the highest solubiity (of 37 g) at this temprature of `20^(@)C`.
(D) the given data shows that the solubility of a salts increase on increaseing the temperature .