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8 g naoh and 4.9g h2so4 are present in one litre of the solution . What is its ph |
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Answer» The pH of the solution is 13Explanation:MOLECULAR weight of NAOH = 40Weight of NaOH = 8gMoles of NaOH = Weight/Molecular weight = 8/40 = 0.2 molesMolecular weight of H₂SO₄ = 98Weight of H₂SO₄ = 4.9gMoles of H₂SO₄ = Weight/Molecular weight = 4.9/98 = 0.05 moles1 mole of NaOH will give = 1 mole of OH⁻ ions0.2 moles of NaOH will give = 0.2 moles of OH⁻ ions1 mole of H₂SO₄ will give = 2 moles of H⁺ ions0.05 moles of H₂SO₄ will give = 0.05 × 2 = 0.1 moles of H⁺ ionsThus 0.1 moles of H⁺ will be neutralised by 0.1 moles of OH⁻ ionsAnd 0.1 moles of OH⁻ ions will be leftConcentration of OH⁻ ions = 0.1/1 = 0.1 Mor, [OH⁻ ] = 0.1 MpOH = -log[OH⁻ ] = -log(0.1) = -log10⁻¹ = 1We know thatpH + pOH = 14Thus, pH + 1 = 14or, pH = 14 - 1 = 13Therefore pH of the solution is 13 |
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