USA: +1 (725) 712-1730 
Sign in
Acetic acid, the compound with a distinctive sour taste and pungent smell, has a pKa value of 4.76. What is its Ka value? Express your answer using two significant figures.
Is it a stronger acid or a weaker acid than vitamin C (Ka=6.8×10−5)?
Expert Answer
Given data:
pKa of acetic acid = 4.76
According to the definition of pKa, we can write as mentioned below.
pKa = -Log(Ka)
i.e. Ka = 10-pKa
i.e. Ka = 10-4.76
i.e. Ka = 1.74*10-5
Acetic acid is a weaker acid than vitamin C.
Reason: As the value of acid dissociation constant (Ka) increases, the acid becomes stronger.
Here, (Ka)Acetic acid (= 1.74*10-5) > (Ka)Vitamin C (= 6.8*10-5)
