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# Pls help with Kc Watch

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1. (Original post by alow)
The water was initially colourless. You said it goes purple, which is more purple than colourless. We don't care about the colour of the solid/liquid (of potassium permanganate or C) we're adding, we care about the colour of the solution which we are adding it to.
Right, okay it does ring some bells in my head. Water does goes more purple as you have put it . But in my question, water is not involved though so I am struggling to see why ....
2. (Original post by coconut64)
Right, okay it does ring some bells in my head. Water does goes more purple as you have put it . But in my question, water is not involved though so I am struggling to see why ....
A, B and C are in aqueous solution. AKA dissolved in water.
3. (Original post by alow)
A, B and C are in aqueous solution. AKA dissolved in water.
Okay, pls bear with me I am so near to understanding it now.
So 1 is due to the increase of conc of C. 2 is due to the increase in conc of A and B. But still don't get how 3 occurs.
4. (Original post by coconut64)
Okay, pls bear with me I am so near to understanding it now.
So 1 is due to the increase of conc of C. 2 is due to the increase in conc of A and B. But still don't get how 3 occurs.
1. Yes, the addition of C immediately makes the blue colour darker.

2. Some of that added C is converted to A and B, lightening the blue colour. [A] and [B] increase.

3. However, for Kc to remain constant, [C] is still higher than before the addition of extra C.
5. (Original post by alow)
1. Yes, the addition of C immediately makes the blue colour darker.

2. Some of that added C is converted to A and B, lightening the blue colour. [A] and [B] increase.

3. However, for Kc to remain constant, [C] is still higher than before the addition of extra C.
I think I get it now. So for all reactions, when you increase the conc of a certain chemical, only some of it (not all) will be converted into other chemical? For example c in this question??
6. (Original post by coconut64)
I think I get it now. So for all reactions, when you increase the conc of a certain chemical, only some of it (not all) will be converted into other chemical? For example c in this question??
If it's an equilibrium and temperature is constant, yes. Only enough converts to restore the equilibrium.
7. (Original post by alow)
If it's an equilibrium and temperature is constant, yes. Only enough converts to restore the equilibrium.
Thanks for helping as always.
8. (Original post by coconut64)
Thanks for helping as always.
No problem
9. K.C < Thought he was back ^^

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