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Q78 (NDA-I/2025) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Basic chemical principles Answer Verified

Which one of the following statements is NOT correct ?

Result
Your answer: —  ·  Correct: B
Explanation

The pH scale is used to measure the hydrogen ion concentration [H+] in a solution. It is defined as the negative logarithm (base 10) of the hydrogen ion concentration, expressed as pH = -log[H+]. Because of this negative logarithmic relationship, the pH value is inversely proportional to the hydrogen ion concentration. Therefore, as the hydrogen ion concentration increases, the pH value decreases, making statement 2 incorrect. The scale generally ranges from 0 to 14, where 7 is neutral, values below 7 are acidic (high [H+]), and values above 7 are basic (low [H+]). The 'p' in pH originates from the German word 'potenz', which means power or exponent, referring to the power of 10 used in the concentration calculation.

Sources

  1. [1] https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/ph
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