Two buffer solutions P & Q with pH values 4.0 and 6.0 are prepared from acid HA and the salt KA . Both the buffer are 0.5 M in HA . The pH of the mixture of the solution obtained by mixing equal volumes of the two buffers is (pKa of acid =5)

Two buffer solutions P & Q with pH values 4.0 and 6.0 are prepared fro

1.	Two buffer solutions P & Q with pH values 4.0 and 6.0 are prepared from acid HA and the salt KA . Both the buffer are 0.5 M in HA . The pH of the mixture of the solution obtained by mixing equal volumes of the two buffers is (pKa of acid =5)
Answer» `5. 69` `4.71` ` 6. 71` `4. 301` Solution :`pH_1 = PKA +log ""( S_1)/(A) ` ` 4 = pKa +log ""( S_1)/(0.5) = 5+ log ""( S_1)/(0.5)` ` PH_2 =pKa +log "" (S_2)/(A) ` ` 6= pKa +log ""( S_2)/(0.5)= 5 +log ""(S_2)/( 0.5)` ` S_1 =0.05 ,S_2 =5` o mixing , pH =pKa ` + log ""(V_5 +0.05 V)/( 0.5 XX 2V) ` `= 5 +log ""( 5.05)/( 0.5 xx 2 ) = 5.7`