JEE MAIN - Chemistry (2021 - 26th August Morning Shift - No. 8)
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 :
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 :
Statement I is false but Statement II is true
Statement I is true but Statement II is false
Both Statement I and Statement II are true
Both Statement I and Statement II are false
Explanation
Titration curve for strong acid and weak base initially a buffer of weak base and conjugate acid is :
_26th_August_Morning_Shift_en_8_3.png)
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.
_26th_August_Morning_Shift_en_8_4.png)
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.
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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