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GATE 2020 CE (CE1) – Question 27

Water and Waste Water Quality and Treatment · Water quality standards, parameters and water quality index · 1 mark · Multiple choice

35.67 mg HCl is added to distilled water to make 1 litre solution. Atomic weights H = 1 and Cl = 35.5. Neglect water dissociation. Find pH.

  1. 3.50
  2. 3.01
  3. 2.50
  4. 2.01

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Correct answer: (B) 3.01

Explanation

HCl molar mass is 36.5 g/mol. Strong-acid concentration is $0.03567/36.5=0.00097726$ mol/L. Hence $pH=-\log_{10}(0.00097726)=3.01$. **B**.