The dissociation constants for acetic acid and
HCN at 25°C are 1.5*10 6 and 4.5*10-10
respectively. The equilibrium constant for the
equilibrium, CN+CH,COOHHCN+CH,COO
would be
(AIPMT (Prelims) 2000)
(1) 3.0 * 10-5
(2) 3.0 * 104
(3) 3.0 * 10°
(4) 3.0 * 109
Answers
Answered by
1
Explanation:
The dissociation constants for acetic acid and HCN at 25
o
C are 1.5×10
−5
and 4.5×10
−10
respectively. The equilibrium constant for the equilibrium CN
−
+CH
3
COOH⇌HCN+CH
3
COO
−
would be 3×10
4
.
CH
3
COOH⇌CH
3
COO
−
+H
+
;K
1
=1.5×10
−5
...(i)
HCN⇌H
+
+CN
−
;K
2
=4.5×10
−10
...(ii)
Reverse equation (ii)
H
+
+CN
−
⇌HCN;K
3
=
K
2
1
=
4.5×10
−10
1
...(iii)
Add equation (i) and (iii) to get K
CN
−
+CH
3
COOH⇌HCN+CH
3
COO
−
K=K
1
×K
3
=1.5×10
−5
×
4.5×10
−10
1
=3×10
4
.
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