NEETChemistryIonic EquilibrumMCQ+4 / −1
Buffer solutions have constant acidity and alkalinity because
- Athese give unionised acid or base on reaction with added acid or alkali
- Bacids and alkalies in these solutions are shielded from attack by other ions
- Cthey have large excess of H+ or OH ions
- Dthey have fixed value of pH
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Correct answer: A
For this example,
CH3COOH ⇌ CH3COO– + H+ ;
CH3COONa ⇌ CH3COO– + Na+
when few drops of HCl are added to this buffer,
the H+ of HCl immediatly combine with
CH3COO– ions to form undissociated acetic
acid molecules. Thus there will be no H+ ions to
combine with CH3COO– ions to form
undissociated acetic acid molecules. Thus there
will be no appreciable change in its pH value.
Like wise if few drops of NaOH are added, the
OH– ions will combine with H+ ions to form
unionised water molecule. Thus pH of solution
will remain constant.
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