A solution contains 35 grams of KNO3 dissolved in 100 grams of water at 40°C. How much more KNO3 would have to be added to make it a saturated solution?
(1) 29 g (3) 12 g
(2) 24 g (4) 4 g


Sagot :

The solubility of  at 40 C is around 64 g in 100 g water  ot 0.64 g KNO3 in 100 g water.  

Therefore 64 g KNO3  in 100 g water is required for satured solution.

 According to the problem  there are 35 grams of KNO3 dissolved in 100 grams  water  

So we need 64 g-35 g= 29 g more KNO3  

Hence the correct answer is 1  

Solubility:

When the maximum amount of solute is dissolve in the solvent is called solubility. On the basic of solubility the solution are following types:

Saturate solution:

A solution which contains the maximum amount of dissolved solute at the equilibrium is called saturated solution.  

Un-saturate solution:

A solution which contains lesser amount of solute as compare to saturated solution.  It will be able to dissolver more solute.  

Super -Saturate solution:

A solution which contains the more dissolved amount of solute as compare to saturated solution.

A saturated solution is a solution that can not dissolve any more solute in it. The amount of potassium nitrate that can be dissolved to make a saturated solution is 29 gm.

What is solubility?

The capability of the solute to get dissolved in the solvent to form a saturated solution is called solubility.

The solubility of potassium nitrate in 100 gm of water at 40 degrees celsius is 64 gm. Hence, 64 gm of potassium nitrate is required in 100 gm of water to form a saturated solution.

In the question, the amount of potassium nitrate in 100 gm water is 35 gm so, the amount of the potassium nitrate required more will be,

[tex]64 - 35 = 29 \;\rm gm[/tex]

Therefore, option (1) 29 gm of potassium nitrate should be added more.

Learn more about solubility here:

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