Which of the following anions would precipitate the most in the reaction of sodium salts with magnesium chloride? What could be done to increase the solubility of the precipitate?

Question

Which of the following anions would precipitate the most in the reaction of sodium salts with magnesium chloride? What could be done to increase the solubility of the precipitate?

$a)$ $a)$ ${SO}_{4}^{2 -}$ $"SO"_4^(2-)$
$b)$ $b)$ ${HCO}_{3}^{-}$ $"HCO"_3^(-)$
$c)$ $c)$ ${CO}_{3}^{2 -}$ $"CO"_3^(2-)$
$d)$ $d)$ ${NO}_{3}^{-}$ $"NO"_3^(-)$

1 Answer

Impact of this question

2172 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2017-08-09T19:56:59

Likely, sulfate... but you would have to do the experiment yourself to verify this.

...And this reaction is given by...

${Na}_{2} {SO}_{4} (a q) + {MgCl}_{2} (a q) \to NaCl (a q) + {MgSO}_{4} (s)$ $"Na"_2"SO"_4(aq) + "MgCl"_2(aq) -> "NaCl"(aq) + "MgSO"_4(s)$

$s_{M g S O_{4}} \approx 35.1 g/100 mL water$ $s_(MgSO_4) ~~ "35.1 g/100 mL water"$ at $25^{\circ} C$ $25^@ "C"$

which is quite high. But contrary to common expectation, by boiling, the solubility decreases.

Magnesium sulfate is one of the only examples I can think of that decreases in solubility at higher temperatures. You can read more about this here, but in short...

Increasing the temperature for ${MgSO}_{4} (a q)$ $"MgSO"_4(aq)$ shifts the equilibrium between crystallization and [dissolution + solvation], towards crystallization, because its dissolution process is exothermic. $DeltaH ~~ -"91.2 kJ/mol"$ .

As for the others...

$s_(Mg(HCO_3)_2) = "0.077 g/100 mL water"$ at $25^@ "C"$

$s_(MgCO_3) = "0.0139 g/100 mL water"$ at $25^@ "C"$

$s_(Mg(NO_3)_2) = "large"$ at $25^@ "C"$

And the first two clearly precipitate at room temperature and pressure. Where on Wikipedia did I get this data?

Science

Math

Humanities

... and beyond

Which of the following anions would precipitate the most in the reaction of sodium salts with magnesium chloride? What could be done to increase the solubility of the precipitate?

$a)$ $a)$ ${SO}_{4}^{2 -}$ $"SO"_4^(2-)$
$b)$ $b)$ ${HCO}_{3}^{-}$ $"HCO"_3^(-)$
$c)$ $c)$ ${CO}_{3}^{2 -}$ $"CO"_3^(2-)$
$d)$ $d)$ ${NO}_{3}^{-}$ $"NO"_3^(-)$

1 Answer

Related questions

Impact of this question

Science

Math

Humanities

... and beyond

Which of the following anions would precipitate the most in the reaction of sodium salts with magnesium chloride? What could be done to increase the solubility of the precipitate?

a)a)a) "SO"_4^(2-)SO2−4"SO"_4^(2-) b)b)b) "HCO"_3^(-)HCO−3"HCO"_3^(-) c)c)c) "CO"_3^(2-)CO2−3"CO"_3^(2-) d)d)d) "NO"_3^(-)NO−3"NO"_3^(-)

1 Answer

Related questions

Impact of this question

$a)$ $a)$ ${SO}_{4}^{2 -}$ $"SO"_4^(2-)$
$b)$ $b)$ ${HCO}_{3}^{-}$ $"HCO"_3^(-)$
$c)$ $c)$ ${CO}_{3}^{2 -}$ $"CO"_3^(2-)$
$d)$ $d)$ ${NO}_{3}^{-}$ $"NO"_3^(-)$