The Student Room Group

BaCl and CaCl solution tests

Hey guys, today is not my day! :frown:

Check this past paper exercise for A level chem.

How would you distinguish between Barium Chloride and Calcium Chloride?
State in each case what would you see as a result of the test in each solution.

I guess it would be easy to heat them on a flame and test the colour, but why is it talking about solutions??

Anyone has any suggestion about it please?
Original post by _Simo_
Hey guys, today is not my day! :frown:

Check this past paper exercise for A level chem.

How would you distinguish between Barium Chloride and Calcium Chloride?
State in each case what would you see as a result of the test in each solution.

I guess it would be easy to heat them on a flame and test the colour, but why is it talking about solutions??

Anyone has any suggestion about it please?


With solutions, flame tests aren’t ideal.

Are you aware of the solubility trend of the group 2 hydroxides?
(edited 1 year ago)
Reply 2
I guess, they are less soluble going down the group due to the size of the cation.
Original post by _Simo_
I guess, they are less soluble going down the group due to the size of the cation.

With the hydroxides, they actually get more soluble down the group.
Original post by TypicalNerd
With the hydroxides, they actually get more soluble down the group.

So, if you added NaOH to separate solutions of CaCl2 and BaCl2, what would happen?
Reply 5
There would be more final product in the reaction of Ba compare to Ca
Reply 6
Or less sorry, The calcium hydroxide would precipitate more?
Original post by _Simo_
Or less sorry, The calcium hydroxide would precipitate more?


This is what I wanted to hear. The barium hydroxide, being very soluble wouldn’t precipitate.

Of course, the question expects you to describe what is seen, so you’d have to state the colour of the precipitate.

What colour would you expect a typical group 2 compound to be?
(edited 1 year ago)
Reply 8
All the group 2 compounds are silvery white unless turnished by O2. So i believe it would be white precipitate.
Original post by _Simo_
All the group 2 compounds are silvery white unless turnished by O2. So i believe it would be white precipitate.

It would be a white precipitate.

Your first sentence better describes the group 2 metals, rather than their compounds, though.
(edited 1 year ago)
Reply 10
Ok! Amazing! Thanks a lot for your help. Didn't do much lab stuff yet unfortunately.

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