Respuesta :
Answer:
D. [H+] of the acetic acid solution is greater than that of the hydrocyanic acid solution.
Explanation:
[tex]CH_3 COOH(aq)+ H_2 O(l) <>CH_3 COO^- (aq)+H_3 O^+ (aq)[/tex]
Initial 0.1M 0 0
Change -x +x +x
Equilibrium 0.1M-x +x +x
[tex]Ka =\frac {((x)(x))}{(0.1M-x)}[/tex]
[tex]1.8\times10^{-5}= \frac {x^2}{(0.1M-x)}[/tex]
(-x is neglected) so we get
[tex]1.8\times10^{-5}\times0.1=x^2\\\\x^2=1.8\times10^{-6}[/tex]
[tex]x=\sqrt{x^2}=1.34\times10^{-3} M=H^3 O^{+}[/tex] is the [tex][H^+ ][/tex] concnetration of acetic acid
[tex]HCN(aq)+ H_2 O(l) <>CN^- (aq)+H_3 O^+ (aq)[/tex]
Initial 0.1M 0 0
Change -x +x +x
Equilibrium 0.1M-x +x +x
[tex]Ka =\frac {((x)(x))}{(0.1M-x)}[/tex]
[tex]4.0\times10^{-10}= \frac {x^2}{(0.1M-x)}[/tex]
(-x is neglected) so we get
[tex]4.0\times10^{-10}\times0.1=x^2\\\\x^2=4.0\times10^{-11}[/tex]
[tex]x=\sqrt{x^2}=6.32\times10^{-6} M=H^3 O^{+}[/tex] is the [tex][H^+ ][/tex] concnetration of Hydrocyanic acid
Thus we see here, [H+] of the acetic acid solution [tex]1.34 \times 10^{-3} M[/tex] is greater than that of the hydrocyanic acid solution [tex]6.32 \times10^{-6} M[/tex]
Please note∶
To find [tex][OH^- ][/tex] we use formula [tex][OH^- ]= \frac {kw}{([H^+])}[/tex]
The value of kw is 1.0×10^(-14)
The [tex][OH^- ][/tex] is lesser in each solution
