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The number of moles of NaCl in 3 litres of 3M solution is (a) 1 (b) 3 (c) 9 (d) 27 |
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Answer» The above question is from the CHAPTER 'Some BASIC Concepts of Chemistry'.MOLARITY: Number of moles of solute present in 1 litre of solution is called molarity.Unit of Molarity = Molar (M)•When volume is given in litres,Molarity = Number of moles of solute ÷ Volume of solution in litres•When volume is given in millilitresMolarity = (Number of moles of solute × 1000) ÷ Volume of solution in ml•When mass % and density is given,Molarity = (Mass % × Density × 10) ÷ Molar mass of SoluteGiven question: The number of moles of NaCl in 3 litres of 3 M solution is(a) 1(B) 3(c) 9(d) 27Answer: Molarity = Number of moles of solute ÷ Volume of solution in litres3 M = Number of moles ÷ 3 L3 × 3 = Number of moles ∴ Number of moles of NaCl = 9 Or3 M means 3 moles in 1 litre of solution.⇒ Number of moles in 3 litres solution = 3 × 3 = 9 moles∴ Number of moles of NaCl = 9 (c) 9 is the CORRECT answer. |
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