why use ethanol in preparation of transition metal complex?

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CassieOOL
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Edexcel A level - core practical 12 - preparing a transition metal. Ethanol is added before crystallization & for washing... why use ethanol ?
TIA x
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scimus63
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polar solvent? Will dissolve organics and some non-organics, so a good wide ranging solvent and fairly volatile, so evaporates to leave no residue. Normally ise acetone for washing though rather than alcolols, much more volatile and a good solvent for organics.

hope this helps but not done edexcel A level course.
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CassieOOL
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(Original post by scimus63)
polar solvent? Will dissolve organics and some non-organics, so a good wide ranging solvent and fairly volatile, so evaporates to leave no residue. Normally ise acetone for washing though rather than alcolols, much more volatile and a good solvent for organics.

hope this helps but not done edexcel A level course.
Hiya, thank you sooo much for this (& for replying so fast when it's Christmas too!) Just to check/clarify though:
so the reagents used are hydrated copper(II) sulfate (as [Cu(H2O)6]^2+ ) & NH3 --> [Cu(NH3)4(H2O)2] ^2+] + 4H2O ... if I am correct
- NH3 is polar (trig. pyramial shape with 1 lone pair) &
- obvs the hydrated Cu2+ is charged (altho octahedral shape means even charge distribution)... so both would need a polar solute... Ethanol is polar at the OH end...? (But NP for the alkane chain)?
More volatile than H2O so will crystallise out more easily???

Right???

Thank you again - really appreciated xx
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jack_harrison
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I've just searched around and had a look at the practical sheet for this one. In the recrystallisation, it looks like you add your product to ethanol, cool it down and then filter it. The reason this would work is if the product is fairly soluble in room temp. ethanol, but becomes more insoluble when you cool it down. Presumably the by-products (water) are still soluble in the cold ethanol so stay in solution when the mixture is filtered. As a result, you get rid of all of your impurities when you filter the ethanol off, whilst retaining insoluble crystals of your product in the residue.The cold ethanol is used to wash to get rid of more soluble impurities whilst avoiding dissolving any more product by maintaining the low temperature and poor solubility.The product complex may be less soluble than expected in the polar solvent due to stabilisation of charge by the new ligands, making it less polar, or weaker hydrogen bonding through NH3, but I can't be sure. All you can be sure of is that ethanol was chosen due to this specific behaviour.
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