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What would be the pH of a 0.1 mol L⁻¹ solution of sulfuric acid? (A) Less than 1.0 (B) Exactly 1.0 (C) Between 1.0 and 7.0 (D) Greater than 7.0 - HSC - SSCE Chemistry - Question 8 - 2005 - Paper 1
Question 8
What would be the pH of a 0.1 mol L⁻¹ solution of sulfuric acid? (A) Less than 1.0 (B) Exactly 1.0 (C) Between 1.0 and 7.0 (D) Greater than 7.0
Worked Solution & Example Answer:What would be the pH of a 0.1 mol L⁻¹ solution of sulfuric acid? (A) Less than 1.0 (B) Exactly 1.0 (C) Between 1.0 and 7.0 (D) Greater than 7.0 - HSC - SSCE Chemistry - Question 8 - 2005 - Paper 1
Step 1
What would be the pH of a 0.1 mol L⁻¹ solution of sulfuric acid?
Answer
To determine the pH of a 0.1 mol L⁻¹ solution of sulfuric acid (H₂SO₄), we need to consider that sulfuric acid is a strong acid and dissociates completely in solution:
ightarrow 2H^+ + SO_4^{2-}$$ This implies that for every 1 mole of sulfuric acid, there will be 2 moles of hydrogen ions (H⁺) produced in the solution. Thus, the concentration of H⁺ ions in the 0.1 mol L⁻¹ solution will be: $$[H^+] = 2 imes 0.1 ext{ mol L}^{-1} = 0.2 ext{ mol L}^{-1}$$ Next, we can calculate the pH using the formula: $$ ext{pH} = - ext{log}([H^+])$$ Substituting the concentration into the formula: $$ ext{pH} = - ext{log}(0.2)$$ Calculating that gives approximately: $$ ext{pH} ext{ (in approximate value)} ext{ is less than } 1.0.$$ Therefore, the answer is (A) Less than 1.0.