Respuesta :
Answer: a) pH of a 0.1 M vinegar solution is 2.9
b) It is an acid as pH is less than 7
Explanation:
pH or pOH is the measure of acidity or alkalinity of a solution.
pH is calculated by taking negative logarithm of hydrogen ion concentration.
Acids have pH ranging from 1 to 6.9, bases have pH ranging from 7.1 to 14 and neutral solutions have pH equal to 7.
As vinegar is a weak acid, its dissociation is represented as;
[tex]CH_3COOH\rightleftharpoons H^+CH-3COO^-[/tex]
cM 0 0
[tex]c-c\alpha[/tex] [tex]c\alpha[/tex] [tex]c\alpha[/tex]
So dissociation constant will be:
[tex]K_a=\frac{(c\alpha)^{2}}{c-c\alpha}[/tex]
Give c= 0.1 M
[tex][H^+]=c\times \alpha[/tex]
[tex][H^+]=0.1\times \alpha[/tex]
[tex]1.3\times 10^{-3}=0.1\times \alpha[/tex]
[tex]\alpha=0.013[/tex]
Also [tex]pH=-log[H^+][/tex]
[tex]pH=-log[1.3\times 10^{-3}]=2.9[/tex]
Thus pH of a 0.1 M vinegar solution is 2.9
As pH is less than 7, it is an acid.
