PrepRung
Sign inSign up free

NDA 2020 GAT · General Knowledge · Acids, Bases and Salts · medium

If the hydrogen ion concentration of solution A (pH 3) is compared with solution B (pH 5), then solution A has hydrogen ion concentration that is

Single correct option

If the hydrogen ion concentration of solution A (pH 3) is compared with solution B (pH 5), then solution A has hydrogen ion concentration that is
  1. A. 2 times that of B
  2. B. 100 times that of B
  3. C. 10 times that of B
  4. D. 1/100 of that of B
Show answer and solution

Answer: (B) 100 times that of B

pH = -log[H+], so pH 3 means [H+] = 10^-3 mol/L and pH 5 means 10^-5 mol/L. The ratio is 10^-3 / 10^-5 = 100. The scale is logarithmic, so a difference of two pH units means a hundredfold change, not a twofold change.
Report a mistake

Original question written in the NDA 2020 GAT pattern and checked twice for the correct answer. Not an official question paper. How we write and check questions · Corrections policy · Report a mistake