JEE Main 2021ChemistryIonic EquilibriumPh Buffer And IndicatorsmediumMCQ
JEE Main 2021 — Ionic Equilibrium Question with Solution
From: JEE Main 2021 (Online) 26th August Morning Shift
Question
Given below are two statements.
Statement I : In the titration between strong acid and weak base methyl orange is suitable as an indicator.
Statement II : For titration of acetic acid with NaOH phenolphthalein is not a suitable indicator.
In the light of the above statements, choose the most appropriate answer from the options given below :
Choose an option
▸Show full solutionCorrect option: B
Correct answer
BStatement I is true but Statement II is false
Step-by-step explanation
Titration curve for strong acid and weak base initially a buffer of weak base and conjugate acid is :
Formed, thus pH falls slowly and after equivalence point, so the pH falls sharply so methyl orange, having pH range of 3.2 to 4.4 will weak as indicator. So, statement I is correct.
Titration curve for weak acid and strong base (NaOH)
Initially weak acid will form a buffer so pH increases slowly but after equivalence point. It rises sharply covering range of phenolphthalein so it will be suitable indicator so statement II is false.
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