The pH values of four solutions A, B, C and D are 5, 12, 8 and 9 respectively. Arrange them in the increasing order of their hydroxyl ion concentration, Which solution among them has strong acidic property? Explain what happens if our mouth contains the pH of solution 'A'

Explanation

i) 12 >9>8> 5 or B>D>C>A
ii) In solution .A. has strong acidic property.
iii) When the pH in the mouth is 5(A) tooth decay starts. Bacteria present in the mouth produces acid by degradation of sugar and food particles which remain in the mouth after eating. This can lead to tooth decay. Therefore we should brush our teeth with toothpaste because it contain base.