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NTA Abhyas 2020
Exam
NTA Abhyas
Year
2020
Subject
Chemistry
Chapter
Ionic Equilibrium

NTA Abhyas 2020 · Chemistry · Ionic Equilibrium

At 25 ^ o C,pH range of phenolphthalein is 8 - 10. At 100 ^ o C, pH...

At 25oC,pH{25}^{o}C,pH range of phenolphthalein is 8−10.8 - 10. At 100oC,pH{100}^{o}C, \text{pH} range of phenolphthalein would be -

Options

  1. ApH\text{pH} range remain unaffected by the temperature
  2. BpH\text{pH} range is altered to 77 - 99
  3. CpH\text{pH} range is altered to 7\text{7} - 11\text{11}
  4. DpH\text{pH} range is altered to 8\text{8} - 11\text{11}

Correct answer

B. pH\text{pH} range is altered to 77 - 99

Step-by-step solution

The pH\text{pH} range of the indicator is pKIn±1.p{K}_{In} \pm 1. On increase in temperature pKInp{K}_{In} decreases therefore pH\text{pH} range of indicator decreases.
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