Buffer solutions have constant acidity and alkalinity because

Options

A. they have large excess of `H^(+)` of `OH^(-)` ions
B. they have fixed value of pH
C. these give unionized acid or base on reaction with added acid or alkali
D. acids and alkalies in these solutions are shielded from attack by other ions

Answer

C

Explanation

Consider a buffer of `CH_(3)COOH+CH_(3)+COONa`
Addition of acid `: H^(+)+CH_(3)COO^(-) to CH_(3)COOH`
Weak acid
Addition of alkali
`OH^(-)+CH_(3)COOH to H_(2)O+CH_(2)COO^(-)`
Weak electrolyte)
The the additin of acid of alkali does not cause any change in pH,