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group 7 Alevel chemistry

guys am so confuse with this whole displacement reaction I've watched several videos but am still confused
for kcl and bromide shouldn't the observation be green solution has chlorine will displace bromide but apparently its a yellow\orange solution how comes
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Original post by laraaaaaaa.ox
guys am so confuse with this whole displacement reaction I've watched several videos but am still confused
for kcl and bromide shouldn't the observation be green solution has chlorine will displace bromide but apparently its a yellow\orange solution how comes


chlorine is more reactive hence displaces the bromine in the initial bromine containing compound. hence the chlorine becomes part of the compound and "kicks the bromine out". hence the solution becomes brown as that is the colour of bromine in solution. The bromine has been "isolated" from its compound and hence shows its colours. Not proper chemistry terminology lol but its the way i used to think about it. Hope that Helps!!
Original post by laraaaaaaa.ox
guys am so confuse with this whole displacement reaction I've watched several videos but am still confused
for kcl and bromide shouldn't the observation be green solution has chlorine will displace bromide but apparently its a yellow\orange solution how comes

Chlorine will displace bromide ions, but the example mentioned (KCl and Br2) will not involve a displacement reaction, because Br2 isn’t a strong enough oxidising agent to remove the extra electron from the Cl^- ion in KCl.
(edited 1 year ago)
Original post by Khunal
chlorine is more reactive hence displaces the bromine in the initial bromine containing compound. hence the chlorine becomes part of the compound and "kicks the bromine out". hence the solution becomes brown as that is the colour of bromine in solution. The bromine has been "isolated" from its compound and hence shows its colours. Not proper chemistry terminology lol but its the way i used to think about it. Hope that Helps!!


thank you
Original post by laraaaaaaa.ox
guys am so confuse with this whole displacement reaction I've watched several videos but am still confused
for kcl and bromide shouldn't the observation be green solution has chlorine will displace bromide but apparently its a yellow\orange solution how comes


I think it may be worth explaining the group 7 ‘reactivity trend’.

Note that ‘halogen’ refers to a group 7 element and ‘halide’ refers to a salt formed in which the group 7 element forms a monatomic (single-atomed) anion with a charge of -1.

Going down the group, the halogen atoms get bigger and they have more electrons. This makes it harder for the halogens lower down the group to gain electrons and harder for the corresponding halides lower down the group to hold onto their extra electrons. These observations are both because the bigger the atom/ion is, the further the negative electrons are from the positive nucleus (hence the attraction is weaker) and the more electrons the atom/ion has, the greater the ‘shielding effect’ (repulsion against the outer electrons) is, which makes picking up and holding onto an electron harder.

So what this results in is the halogens towards the top of the group being good at displacing the halides of the group 7 elements at the bottom of the group.

Ignoring astatine and astatide ions:

F2 can displace any other halide (Cl^-, Br^- and I^-) and F^- cannot be displaced by any halogen.

Cl2 can displace Br^- and I^- ions and Cl^- can only be displaced by F2

Br2 can only displace I^- ions and Br^- can be displaced by F2 and Cl2

I2 cannot displace any other halide ions, but I^- can be displaced by F2, Cl2 and Br2
Original post by TypicalNerd
I think it may be worth explaining the group 7 ‘reactivity trend’.

Note that ‘halogen’ refers to a group 7 element and ‘halide’ refers to a salt formed in which the group 7 element forms a monatomic (single-atomed) anion with a charge of -1.

Going down the group, the halogen atoms get bigger and they have more electrons. This makes it harder for the halogens lower down the group to gain electrons and harder for the corresponding halides lower down the group to hold onto their extra electrons. These observations are both because the bigger the atom/ion is, the further the negative electrons are from the positive nucleus (hence the attraction is weaker) and the more electrons the atom/ion has, the greater the ‘shielding effect’ (repulsion against the outer electrons) is, which makes picking up and holding onto an electron harder.

So what this results in is the halogens towards the top of the group being good at displacing the halides of the group 7 elements at the bottom of the group.

Ignoring astatine and astatide ions:

F2 can displace any other halide (Cl^-, Br^- and I^-) and F^- cannot be displaced by any halogen.

Cl2 can displace Br^- and I^- ions and Cl^- can only be displaced by F2

Br2 can only displace I^- ions and Br^- can be displaced by F2 and Cl2

I2 cannot displace any other halide ions, but I^- can be displaced by F2, Cl2 and Br2


Thank you so much
sorry for joining the conversation so late but this page may help you a bit

https://www.science-revision.co.uk/halogen_displacement+reactions.html
Original post by laraaaaaaa.ox
guys am so confuse with this whole displacement reaction I've watched several videos but am still confused
for kcl and bromide shouldn't the observation be green solution has chlorine will displace bromide but apparently its a yellow\orange solution how comes

Which spec. do you do?
Original post by Pigster
Which spec. do you do?


Aqa

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