i posted this already but i got the answer for someone elses question.
the pka of acetone is CH3COCH3 is 19.3 which of these bases is strong enough to deprotonate acetone?
a)KOH (pka of H20 = 15.7)
b)Na+ -C(triplebond)CH (pka of C2H2 = 25)
c)NaHCO3 (pka of H2CO3 = 6.4)
d)NaOCH3 pka of CH3OH = 15.6)
i know the answer is b but why is it b? is it because the pka is high?
To determine which of the given bases is strong enough to deprotonate acetone (CH3COCH3), you need to compare their pKa values to the pKa of acetone.
The pKa of acetone is given as 19.3. A lower pKa value indicates a stronger acid, while a higher pKa value indicates a weaker acid. In this case, we are looking for a base strong enough to deprotonate acetone, which means we need a base with a pKa value lower than 19.3.
Let's analyze the pKa values of the given bases:
a) KOH (pKa of H2O = 15.7): The pKa of water is lower than the pKa of acetone. While KOH is a strong base, its pKa is not low enough to deprotonate acetone.
b) Na+ -C(triple bond)CH (pKa of C2H2 = 25): The pKa of acetylene (C2H2) is higher than the pKa of acetone. Since we need a base with a lower pKa value, this option is not suitable.
c) NaHCO3 (pKa of H2CO3 = 6.4): The pKa of carbonic acid (H2CO3) is much lower than the pKa of acetone. While NaHCO3 is a weak base, its pKa is lower than 19.3 and can deprotonate acetone.
d) NaOCH3 (pKa of CH3OH = 15.6): The pKa of methanol (CH3OH) is lower than the pKa of acetone. However, NaOCH3 is a strong base with a higher pKa value and is suitable for deprotonating acetone.
So, based on the given options, option b) Na+ -C(triple bond)CH is the strongest base and is thus capable of deprotonating acetone.