From the following table `{:("Buffer solution ", "Vol .of 0.1 M weak acid ", "Vol. of . 0.1 M sodium salt of weak acid "),(I,4.0, 4.0 ),(II, 4.0,40.0 ),( III, 40.0 , 4.0),(IV, 0.1,10):}`
Which of the two sets of buffer solutions have least pH ?

Options

A. `I & II`
B. ` I & III`
C. ` II & III`
D. ` II & IV `

Answer

B

Explanation

Buffer -1 ` pH =P^(ka) j+log ""(4)/(4) rArr pH =P^(Ka) `
Buffer -2
` pH = P^(Ka) +log ""( 40)/(4) rArr pH =P^(Ka) +1`
Buffer -3
` pH =P^(Ka) +log ""(4)/(40 ) rArrpH =P^(Ka) -1 `
Buffer -4` pH =P^(Ka) +log ""(10)/(0.1) rArrpH= P^(Ka+2)`