Milk (lowest acidity) < Coffee < Orange juice < Soda pops < vomit < Battery acid (highest acidity)
explanation :
pH values of all :
battery acid pH = 1.0
vomit pH = 2.0
soda pop pH = 2.5
orange juice pH = 3.5
coffee pH = 5.0
milik pH = 6.5
pH value is lesser acidity is more . high pH indicate lesser acidic nature