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Why do alcohols not react with NaOH?
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thegreenchildren
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In the past paper mark scheme it says Phenol reacts with NaOH but Alcohols do not react with NaOH. Why is this? This is not mentioned in my book. I am doing OCR Salters A2.
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EierVonSatan
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hicong
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Phenol is a VERY weak acid as the phenol molecules have weak tendencies to lose the H+ ion from the hydroxyl group. Alcohols are not 
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thegreenchildren
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#4
(Original post by hicong)
Phenol is a VERY weak acid as the phenol molecules have weak tendencies to lose the H+ ion from the hydroxyl group. Alcohols are not
Phenol is a VERY weak acid as the phenol molecules have weak tendencies to lose the H+ ion from the hydroxyl group. Alcohols are not
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kalika_amz
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(Original post by thegreenchildren)
In the past paper mark scheme it says Phenol reacts with NaOH but Alcohols do not react with NaOH. Why is this? This is not mentioned in my book. I am doing OCR Salters A2.
In the past paper mark scheme it says Phenol reacts with NaOH but Alcohols do not react with NaOH. Why is this? This is not mentioned in my book. I am doing OCR Salters A2.
for something to react with naoh (a base) it must be a fairly strong acid (proton donor) because it needs to donate sufficent h+
alchols dont do this- the r-o- ion they form is unstable because charge is concentrated on the o- atom so there is no electron delocation. this means that the r-o- ion is unstable so position of equillibrium lies to the left. rather than donating h+, alcohols are more likely to accept h+
whereas
phenols form an r-o- ion where the - charge is delocalised over the benzene ring that the o is attached to. the r-o- ion is therefore more stable and so the position of equillibrium lies to the right and so phenols donate h+, forming stronger acid
acid + base (naoh) --> salt + h20
hope this helps and good luck for the exam on mon!
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kalika_amz
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thegreenchildren
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#7
(Original post by kalika_amz)
hey, i'm doing ocr salters b too..
for something to react with naoh (a base) it must be a fairly strong acid (proton donor) because it needs to donate sufficent h+
alchols dont do this- the r-o- ion they form is unstable because charge is concentrated on the o- atom so there is no electron delocation. this means that the r-o- ion is unstable so position of equillibrium lies to the left. rather than donating h+, alcohols are more likely to accept h+
whereas
phenols form an r-o- ion where the - charge is delocalised over the benzene ring that the o is attached to. the r-o- ion is therefore more stable and so the position of equillibrium lies to the right and so phenols donate h+, forming stronger acid
acid + base (naoh) --> salt + h20
hope this helps and good luck for the exam on mon!
hey, i'm doing ocr salters b too..
for something to react with naoh (a base) it must be a fairly strong acid (proton donor) because it needs to donate sufficent h+
alchols dont do this- the r-o- ion they form is unstable because charge is concentrated on the o- atom so there is no electron delocation. this means that the r-o- ion is unstable so position of equillibrium lies to the left. rather than donating h+, alcohols are more likely to accept h+
whereas
phenols form an r-o- ion where the - charge is delocalised over the benzene ring that the o is attached to. the r-o- ion is therefore more stable and so the position of equillibrium lies to the right and so phenols donate h+, forming stronger acid
acid + base (naoh) --> salt + h20
hope this helps and good luck for the exam on mon!
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sfhdfhdvfsgr
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kalika_amz
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#9
(Original post by thegreenchildren)
Thanks for your help! I kind of understand now but what does electron de location mean? And just to make sure, when you say the equilibrium lies to the left you mean that theres more of the alcohol and when it lies to the right there is more of the ion?
Thanks for your help! I kind of understand now but what does electron de location mean? And just to make sure, when you say the equilibrium lies to the left you mean that theres more of the alcohol and when it lies to the right there is more of the ion?
electron delocalisation is where your electron charge (which is negative) is spread (delocalised)
so in the case of phenols, the electron chanrge is spread, delocalised, over the benzene ring..
yeah
so: r-oh + h20 --> r-o- + h30+
(pretend the arrow is the equilibrium arrow)
so lies to the left would be the left hand side so the r-oh
and lies to the right is the right hand side the r-o- ion
hope this is okay
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thegreenchildren
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#10
(Original post by kalika_amz)
sorry for the late reply
electron delocalisation is where your electron charge (which is negative) is spread (delocalised)
so in the case of phenols, the electron chanrge is spread, delocalised, over the benzene ring..
yeah
so: r-oh + h20 --> r-o- + h30+
(pretend the arrow is the equilibrium arrow)
so lies to the left would be the left hand side so the r-oh
and lies to the right is the right hand side the r-o- ion
hope this is okay
sorry for the late reply
electron delocalisation is where your electron charge (which is negative) is spread (delocalised)
so in the case of phenols, the electron chanrge is spread, delocalised, over the benzene ring..
yeah
so: r-oh + h20 --> r-o- + h30+
(pretend the arrow is the equilibrium arrow)
so lies to the left would be the left hand side so the r-oh
and lies to the right is the right hand side the r-o- ion
hope this is okay
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Rhmanapaa
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Ashsh
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My next question is.. if R --O- ion is unstable due to concentration of negative charge ion on oxygen atom then why it only takes H ion to get neutralize itself, it may take Na also ( From NaOH) to form R-----O-----Na and H2O
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