Question

question 28

this fertilizer is dis molarity of Cu2+? *4.28. For which of the following compounds is it possible to make a 1.0 M solution at 20°C? a. CuSO, solubility = 32.0 g/100 mL b. Ba(OH),, solubility = 3.9 g/100 mL c. FeCl, solubility = 68.5 g/100 mL d. Ca(OH),, solubility = 0.173 g/100 mL

Answer 1

In order to prepare 1M solution , in 1liter water
amount of solute dissolved must be = molar mass of solute

for CUSO4
molar mass=159.609 g/mol
get 1 M solution: 159.609 g CUSO4 in 1L
32 g CuSO4 is soluble in 100 ml water
So Maximum of 320 g can be dissolved in 1L [100ml]
So it is possible get 1 M solution: 159.609 g CUSO4 can be dissolved to malke 1 M
CuSO4 it is possible
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Ba(OH)2 molar mass=171.34 g/mol
SO in 1 L 171.34 g Ba(OH)2 must be dissolved to get 1 M solution
Since in 100 ml only 3.9 g is soluble:In 1L, 39 g Ba(OH)2 is possible.So
not possible to prepare 1M
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FeCl2=126.751 g/mol
SO in 1L , 126.751g FeCl2 we get 1M
Since its solubility is 68.5 in 100ml
685 g FeCl2 will be soluble in 1L
So 1M solution of FeCl2 is possible
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Ca(OH)2, molar mass=74.093 g/mol
SO in 1L, 74.093 g Ca(OH)2 we get 1M
But only 1.73 g is possible,since it has very low solubility
So 1M Ca(OH)2 is not possible
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{{Note that if we increase temperature, solubility  will also increase}}

:)