Question

2mL of I2/KI aqueous solution and 2 mL of varsol are added. These two are immiscible, so they form two layers. 2 drops of sodium thiosulphate are added to this. What happened was that Phase A (varsol) turned lighter than control (pink), and Phase B (I2/KI) turned lighter than control (yellow)

Answer 1

So, why did this happen when taking into account the chemistry perspective?

Answer 2

I figured out.

Answer 3

I'm not sure about the varsol but i do know the thiosulfate reduces the iodine in solution to iodide which is why b goes clear.

Answer 4

2 S2O32−(aq) + I2(aq) → S4O62−(aq) + 2 I−(aq)

Answer 5

Wikipedia FTW

Answer 6

This occurred in both solutions, and I interpreted it from there.

Answer 7

Ok could you help me with the last question I have.

Answer 8

It is this:

Answer 9

sure

Answer 10

You have this solution:

Put 5 mL of 0.1M magnesium chloride into a test tube. Add 5mL of 1M ammonium solution. Shake to mix and observe. Add 1g of ammonium chloride and shake well. Observe again

What are the possible reactions and/or equilibria that can be taking place here?

Answer 11

This is what I got so far:

NH3(aq) + H2O(l) <=> NH4+(aq) + OH-(aq)
^- because it was an aqueous solution of NH3(aq) <-- I forgot to mention that.

Answer 12

and then there is NH3, Mg, Cl
NH3 + MgCl2 --> NO REACTION?

Answer 13

Professor's reply: I can suggest that you consider what other possible products could be made from the combination of ions that you have present in your solution(s). You are missing some key reactions/equilibria in your analysis.

Answer 14

He probably means MgOH2. Becuase when NH3 goes into water it will form NH4 and OH ions. Which means that MgOH2 will probably form with NH4Cl added. I'll come up with a link or better answer.

Answer 15

is magnesium hydroxide a slighty soluble comp/ d

Answer 16

?

Answer 17

Yes it is

Answer 18

\[Mg^{2+}_{(aq)} + 2NH^3_{(aq)} + 2H_2O_{(l)} <==> Mg(OH)_{2(s)} + 2NH4^+_{(aq)}\]

Answer 19

then on addition of NH4 you can see how it would shift left and the ppt will dissolve

Answer 20

It will shift left due to common ion NH3?

Answer 21

because I had:
NH3(aq) + H2O(l) <=> NH4+(aq) + OH-(aq)

Answer 22

SORRY

Answer 23

Common ion NH4+

Answer 24

Common ion NH4+

Answer 25

Yeah.

Answer 26

The equation i gave you will be the first one your professor is looking for. Now just say that on addition of excess NH4+ from the ammonium chloride that the precipitate will dissolve due to le chatlier's principal.

Answer 27

So does that make sense QRA?