[angelku]

Add chlorine bleach to aqueous bromine,and then add dilute HCl.

What is the chemical equation for this reaction?

After that, add hexane to the solution mixture.The colour change in the aqueous layer and hexane layer was observed.

 What is the purpose of using chlorine bleach?

[Borek]

Please read forum rules.

What do you think should happen and why?

[Alpha-Omega]

Please clarify that reaction....Do you mean chlorine is added to a bromine salt.  If that is the case we are talking about simple displacemnt....for the first step anyway.....sounds like organic chemistry to me.....diplacement and substitution.....need more 411....

Chlorine is more reactive than bromine (you know this because chlorine is above bromine in Group 7). Sodium bromide is a salt of bromine that will dissolve in water. So chlorine will displace bromine from sodium bromide solution.

chlorine + sodium bromidesodium chloride + bromine
Cl2(aq) + 2NaBr(aq)  2NaCl(aq) + Br2(aq)

[angelku]

What I mean is that add chlorine bleach and few drops of dilute hydrochloric acid to the aqueous bromine.


Br2+OCl-+Cl-  -->?

I don't know how to write it.
By adding  hexane layer tothe solution mixture to confirm the presence of Br2.But how about  chlorine bleach ?

[Arkcon]

angelku: try and look up what chlorine bleach does, once you have one word, you'll know what it did in your reaction, and why it was needed.  Or see what it did in your reaction, and learn the one word for what chlorine bleach is used for.

[Alpha-Omega]

I think you ran this experiment:

An aqueous solution of a halogen (Cl2, Br2 or I2) is poured into an aqueous halide solution (Cl-, Br- or I-) covered with a layer of hexane. After the liquid has been shaken, the color of the hexane layer is compared to the color of hexane solutions of chlorine, bromine and iodine.

Bromide ion is added to chlorine water. By observing the color of the hexane layer, then you can see that the reaction has produced bromine.
(Note that the hexane layer is above the aqueous layer.)
2Br-(aq ) + Cl2(aq ) --> 2Cl-(aq ) + Br2(aq )

Then in Step 2:
Chloride ion is added to bromine water. By observing the color of the hexane layer, we see that no reaction has occurred.
(Note that the hexane layer is above the aqueous layer.)
2Cl-(aq ) + Br2(aq ) --> No reaction took place

Tell me if I am correct….because the chloride ion will NOT displace the bromide ion.  The addition of the weak HCl demonstrates this.  this entire experiment demonstrates the reactivity of the halogens.

[angelku]

I know that chlorine bleach contains H+,Cl-, HClO .But does it equal to the use of chlorine water to perform the experiment that I mentioned?
I know that chlorine dissolve in water to produce the following equation
Cl2(aq) + H2O(l)  H+(aq) + Cl-(aq) + HClO(aq)

Do you mean  only Cl- rather than HClO which come from chlorine water react Br-to produce Br2 gas?
In writing the equation ,where should  H+ be placed ?

I don't know what you mean the purpose of using weak HCl.What does it demonstrate for?

[Alpha-Omega]

OK you have a 2 Step Process Here RIGHT??

Step 1:

An aqueous solution of a halogen (Cl2, Br2 or I2) is poured into an aqueous halide solution (Cl-, Br- or I-) covered with a layer of hexane. After the liquid has been shaken, the color of the hexane layer is compared to the color of hexane solutions of chlorine, bromine and iodine.

Bromide ion is added to chlorine water. By observing the color of the hexane layer, then you can see that the reaction has produced bromine.
(Note that the hexane layer is above the aqueous layer.)
2Br-(aq ) + Cl2(aq ) --> 2Cl-(aq ) + Br2(aq )

This is the hexane step you say you get.. RIGHT?


Then in Step 2:
Chloride ion is added to bromine water. By observing the color of the hexane layer, we see that no reaction has occurred.
(Note that the hexane layer is above the aqueous layer.)

2Cl-(aq ) + Br2(aq ) --> No reaction took place.

So the purpose of adding that dilute HCL is to show you the relative reactivity of the halogens in the halogen series....NO RXN occurred....is that correct?

I was asking you to confirm this was your process..

Tell me if I am correct….because the chloride ion will NOT displace the bromide ion.

[AWK]

I know that chlorine bleach contains H+,Cl-, HClO .But does it equal to the use of chlorine water to perform the experiment that I mentioned?
I know that chlorine dissolve in water to produce the following equation

should be:
Cl2(aq) + H2O(l)  = H+(aq) + Cl-(aq) + HClO(aq)
Bleach contains Na+, Cl- and ClO-
You add acid to form HClO which is a strong oxidizer

Do you mean  only Cl- rather than HClO which come from chlorine water react Br-to produce Br2 gas?
In writing the equation ,where should  H+ be placed ?

In solution Br2(aq) is formed

I don't know what you mean the purpose of using weak HCl.What does it demonstrate for?

Weak HCl is a nonsense, but such  slips of memory often happen

[angelku]

I know that ClO-in chlorine bleach can oxidise KI but not KBr
By adding HCl to acidify ClO-,HClO becomes  a  strong oxidizing agent to oxidise KBr.
How about thereactin of  KCl react with ClO-?
I don't know how to explain it in terms of Ka,Kc when adding hexane to the solution mixture?