Why can't alcohol react with aqueous NaOH?

In summary, alcohol is able to react with Na (s) but not NaOH (aq). This is because in aqueous NaOH, the reaction occurs between the hydroxide ions (OH-) and the alcohol (R-OH), not the sodium ions (Na+). The equilibrium between OH- and R-O- in solution depends on the pKa of the alcohol. Additionally, if water is present, the alkoxide ions (R-O-) can act as strong bases and deprotonate the water.
  • #1
fluppocinonys
19
1
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Hi, alcohol is able to react with Na (s), but not NaOH (aq)
Why is it so?
In aqueous NaOH, there are mobile Na+ and OH-, so shouldn't alcohol be able to react with Na+ to form salt too?

Many thanks!
 
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  • #2
The reaction will, in fact occur. The correct formula would be:

NaOH + R-OH --> R-ONa + H2O

or if you prefer the net ionic equation:

OH- + R-OH --> R-O- + H2O

where R-OH represents the alcohol. So, in this case, it's the hydroxide reacting with the alcohol, not the sodium ions. The sodium ions are just a spectator in the reaction.

The free energy difference between the products and reactants side of the equation is not very large, however, so there will be some equilibrium between hydroxide ions (OH-) and alkoxide ions (R-O-) in solution, which will depend on the pKa of the alcohol.
 
  • #3
Note that alkoxides are usually bases strong enough to deprotonate water, so if there is water present, you end with alcohol and OH-.

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methods
 

1. Why can't alcohol react with aqueous NaOH?

Alcohol, which is a hydrocarbon compound, does not have any acidic or basic functional groups. This means that it does not contain any hydrogen or oxygen atoms that can be ionized and react with the hydroxide ions in aqueous NaOH.

2. Can any type of alcohol react with aqueous NaOH?

No, only alcohols with acidic functional groups such as carboxylic acids or phenols can react with aqueous NaOH. These alcohols have a hydrogen atom that can be ionized and react with the hydroxide ions in NaOH.

3. Why is aqueous NaOH used to test for the presence of acidic functional groups in alcohols?

Aqueous NaOH is a strong base, meaning it has a high concentration of hydroxide ions. When mixed with an alcohol containing acidic functional groups, it will react and produce a salt and water. This reaction can be used to test for the presence of acidic functional groups in alcohols.

4. How does the reaction between alcohol and aqueous NaOH differ from the reaction between acid and aqueous NaOH?

In the reaction between alcohol and aqueous NaOH, the alcohol acts as the acid and donates a proton to the hydroxide ion in NaOH. This forms a salt and water. In the reaction between acid and aqueous NaOH, the acid donates a proton to the hydroxide ion, forming a salt and water.

5. Can other bases besides aqueous NaOH react with alcohols?

Yes, other strong bases such as KOH or Ca(OH)2 can also react with alcohols containing acidic functional groups. However, the products of the reaction may differ depending on the base used.

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