The dissociation constant of a weak acid is 1 × 10-4 in order to prepare a buffer solution with a pH = 5 the [salt] / [Acid] ratio should be :

Question

The dissociation constant of a weak acid is 1 × 10-4 in order to prepare a buffer solution with a pH = 5 the [salt] / [Acid] ratio should be : (A) 4: 5 (B) 10: 1 (C) 5: 4 (D) 1: 10

Tardigrade Admin · Accepted Answer

beginarrayl pH = p Ka+ log ([ Salt ]/[ Acid ]) 5=- log Ka+ log ([ Salt ]/[ Acid ]) [∵ p Ka=- log Ka] 5=- log [1 × 10-4]+ log ([ Salt ]/[ Acid ]) 5=4+ log ([ Salt ]/[ Acid ]) 5-4= log ( text [Salt] /[ Acid ]) 1= log ([ Salt ]/[ Acid ]) ([ Salt ]/[ Acid ])=10 text i.e., 10: 1 endarray

Q. The dissociation constant of a weak acid is $1 \times 1 0^{- 4}$ in order to prepare a buffer solution with a $p H = 5$ the [salt] / [Acid] ratio should be :

4 : 5

10 : 1

5 : 4

1 : 10

Q. The dissociation constant of a weak acid is 1×10−4 in order to prepare a buffer solution with a pH=5 the [salt] / [Acid] ratio should be :

4 : 5

10 : 1

5 : 4

1 : 10

pH=pKa​+log[Acid][Salt]​5=−logKa​+log[Acid][Salt]​[∵pKa​=−logKa​]5=−log[1×10−4]+log[Acid][Salt]​5=4+log[Acid][Salt]​5−4=log[Acid] [Salt] ​1=log[Acid][Salt]​[Acid][Salt]​=10 i.e., 10:1​

Q. The dissociation constant of a weak acid is $1 \times 1 0^{- 4}$ in order to prepare a buffer solution with a $p H = 5$ the [salt] / [Acid] ratio should be :