The ratio of volumes of `CH_(3)COOH`0.1 (N) to `CH_(3)COONa` 0.1 (N) required to prepare a buffer solution of pH 5.74 is
(given : `pK_(a) " of " CH_(3) COOH " is " 4.74)`

Options

A. `10:1`
B. `5:1`
C. `1:5`
D. `1:10`

Answer

D

Explanation

According to Henderson's Equation :
`pH =pKa + log .("Activity of salt")/("Activity of acid")`
`5.74 =4.74 + log .("Concentration xx Volume (salt)")/("Concentration xx Volume (acid)")`
`5.74 =4.74 + log .("Volume (salt)")/("volume(salt)")`
`["Concentrations are the same"]`
`" log".("Volume (salt)")/("Volume (acid)") =" Antilog " 1=10`
volume (salt) : Volume (acid) =10 : 1