For a given mixture of NaHCO 3 and Na 2 CO 3 , volume of a given HCl required is x ml with phenolphthalein indicator and further y ml required with methyl orange indicator. Hence volume of HCl f

Question

For a given mixture of NaHCO 3 ​ and Na 2 ​ CO 3 ​ , volume of a given HCl required is x ml with phenolphthalein indicator and further y ml required with methyl orange indicator. Hence volume of HCl for complete reaction of original NaHCO 3 ​ is

TestHub · Accepted Answer

Using phenolphthalein:

Na₂CO₃ + HCl → NaHCO₃ + NaCl

1 M (say)

NaHCO₃ + HCl ⎯→ No reaction

Therefore, milliequivalents of Na₂CO₃ = milliequivalents of HCl = $x$ .

Using methyl orange:

NaHCO₃ + HCl ⎯→ NaCl + CO₂ + H₂O

Milliequivalents of NaHCO₃ (from Na₂CO₃) + milliequivalents of NaHCO₃ (original mixture) = $y$ .

Or $x$ + milliequivalents of NaHCO₃ (original mixture) = $y$ .

Milliequivalents of NaHCO₃ (original mixture) = $(y - x)$ .

Therefore, the volume of HCl required = $(y - x)$ ml.

Chemistry - Mole Concept Question with Solution | TestHub

Options:

Doubts & Discussion