Q.1 Here is the question
Phenol is an organic compound with the chemical formula of C6H5OH. Phenol is slightly acidic and can react with dilute sodium hydroxide solution
You are given a mixture of propanone, ethanoic acid and phenol.
Describe a scheme, using the method of liquid-liquid extraction, to separate the chemicals from the mixture.
Here is the ans
Shake the mixture with sodium carbonate solution in a separating funnel.
Add ether to the mixture and shake. Separate the aqueous layer from the mixture. Add excess hydrochloric acid to the aqueous layer to regenerate ethanoic
acid.
Add sodium hydroxide solution to the ether layer and shake.
Separate the aqueous layer from the mixture and add excess hydrochloric acid
to regenerate phenol.
Distill off ether from the ether layer. The liquid left behind is propanone.
Why do we need to add ether????? Also will sodium carbonate react with
phenol??
Q.2 Is crystallization a reversible or irreversible reaction?
Q3. The redox reaction can be reversed under electrolysis i.e. against the
spontaneous path. Is Redox reaction a reversible reaction then ?
Q.4 is the following reaction reversible or irreversible
3Fe + 4H20 >>> Fe3O4 + 4H2
Cu(HCO3)2 -------> CaCO3 + H2O + CO2
Q.5 The higher the temperature , the more acidic an acid is . is it true??
Thx!
Chem 問題高手進 20點
2014-02-20 8:58 pm
回答 (1)
2014-02-20 10:31 pm
✔ 最佳答案
From : http://www.chemguide.co.uk/organicprops/phenol/acidity.htmlThis lack of reaction is actually useful. You can recognise phenol because:It is fairly insoluble in water.It reacts with sodium hydroxide solution to give a colourless solution (and therefore must be acidic).It doesn't react with sodium carbonate or hydrogencarbonate solutions (and so must be only very weakly acidic).
Q.1 Why do we need to add ether????? Also will sodium carbonate react with phenol??
mixture of propanone, ethanoic acid and phenol.
Ethanoic acid is ionized in sodium carbonate solution, phenol is not soluble and exist as solid. Using ether extraction can extract out the propanone.
Q.2 Is crystallization a reversible or irreversible reaction?
The process is reversible.
Q3. The redox reaction can be reversed under electrolysis i.e. against the spontaneous path. Is Redox reaction a reversible reaction then ?
Yes, it is. In the pH meter, It has a probe, this is a calomel electrode. When the pH meter has a steady reading, the calomel electrode is at an equilibrium sate.
Q.4 Is the following reaction reversible or irreversible
3Fe + 4H20 >>> Fe3O4 + 4H2
Cu(HCO3)2 -------> CaCO3 + H2O + CO2
No, the gaseous products formed would escape to the surrounding, and the backward reaction just cannot take place.
Q.5 The higher the temperature , the more acidic an acid is . is it true??
Yes, ionization of the acid molecule involves bond breaking, bond breaking is endothermic. Increase of temperature shift the eqm. to the product side.
2014-02-21 01:41:03 補充：
Q.4 Is the following reaction reversible or irreversible
3Fe + 4H20 >>> Fe3O4 + 4H2
Cu(HCO3)2 -------> CaCO3 + H2O + CO2
In open system, irreversible,
the gaseous products formed would escape to the surrounding, and the backward reaction just cannot take place.
2014-02-21 01:46:11 補充：
字數超額了。
Q.4 Is the following reaction reversible or irreversible
3Fe + 4H20 >>> Fe3O4 + 4H2
Cu(HCO3)2 -------> CaCO3 + H2O + CO2
In open system, irreversible,
the gaseous products formed would escape to the surrounding, and the backward reaction just cannot take place.
2014-02-21 01:47:16 補充：
In closed system, say, in a closed steel container, the gaseous products cannot escape, the reaction can be reversible.
收錄日期: 2021-04-27 20:33:16
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