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JEE Main201911 Jan 2019Morning ShiftChemistrySome Basic Concepts of ChemistryActual

A 10 mg effervescent tablet containing sodium bicarbonate and oxalic acid releases 0.25 ~mL of CO ₂ at T =298.15 ~K and P =1 bar. If molar volume of CO ₂ is 25.0 ~L under such condition, what is the percentage of sodium bicarbonate in each tablet? [Molar mass of . NaHCO ₃=84 ~g ~mol ⁻¹ ]

Options

  1. A0.84
  2. B33.6
  3. C16.8
  4. D8.4

Correct answer

D. 8.4

Step-by-step solution

2 NaHCO ₃+ H ₂ C ₂ O ₄ Na ₂ C ₂ O ₄+2 CO ₂+2 H ₂ O Moles of CO ₂ evolved = 0.25 25 10³ =10⁻⁵ aligned & Moles of NaHCO ₃=10⁻⁵ Mass of NaHCO ₃ &=84 10⁻⁵ ~g &=0.84 10⁻³ ~g =0.84 mg aligned % by weight = 100=8.4 %

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