Magnesium Carbonates Reaction Under Various Test?

  • Thread starter John Ker
  • Start date
  • #1
16
1

Homework Statement


If you had a solution of Magnesium carbonate, what results would you expect from the following four tests: Precipitation Test, Flame Test, Benedicts Reagents Test, Dilute Acid Test.

Could someone take a look at my reasoning to how the Magnesium Carbonate would react under these conditions, thanks!


The Attempt at a Solution


[/B]
Precipitation Test:

MgCO3(aq)+CaCl2(aq) → MgCl2(aq) + CaCO3(s)

When Magnesium Carbonate reacts with Calcium Chloride, it will produce Magnesium Chloride and Calcium Carbonate, Calcium Carbonate is a precipitate in this case, hence the test will be positive.


Flame Test:

When testing for metal ions within the solution, Mg, the metal, does not produce visible light within the spectrum, hence the test will produce no color when placed under the flame.


Benedicts Reagent:

Magnesium Chloride is not a simple sugar, hence it will produce blue under both the room temperature and heated solutions.


Dilute Acid Test:

MgCO3 à Mg+ + CO3-

2H+ + CO3 à H2O + CO2(g)

CO2 will rapidly form, giving a positive to the Dilute Acid Test.
 

Answers and Replies

  • #2
Borek
Mentor
28,635
3,106
what results would you expect from the following four tests: Precipitation Test
Is it really how the question was worded? "Precipitation test" doesn't say anything about anion/cation added, so it can be either positive or negative, depending on what you use.

Other than that your logic looks OK (although I am not convinced about practicality of the calcium carbonate precipitation, magnesium carbonate is rather weakly soluble so the concentration of CO32- will be low, making the precipitation difficult to observe).
 

Related Threads on Magnesium Carbonates Reaction Under Various Test?

  • Last Post
Replies
5
Views
13K
Replies
2
Views
31K
Replies
5
Views
16K
Replies
1
Views
8K
  • Last Post
Replies
15
Views
1K
  • Last Post
Replies
8
Views
44K
  • Last Post
Replies
1
Views
5K
  • Last Post
Replies
8
Views
8K
  • Last Post
Replies
3
Views
8K
Top