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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: Julie Smith on October 31, 2008, 12:11:37 AM

Title: neutralizing weak acids
Post by: Julie Smith on October 31, 2008, 12:11:37 AM

hi, I'm stuck on this problem hopefully someone can help.

question:

calculate the volume of 0.10M NaOH required to neutralize 10mL of 0.10M acetic acid(CH3COOH)

My attempt:

CH3COOH --> H+ + CH3COO
     0.10M         0          0         (initial [  ])
     -x               x          x          (change in [  ])
----------------------------------------------------
  0.10-x            x         x           (equivalence)

ka = 0.000018

therefore, (x)(x)/0.10(assume x is small so I ignored it)=0.000018

x= 0.00134164 =[H+]

therefore, (0.00134164M H+)(0.01L H+)/(0.10M NaOH)=0.000134164L

that number just seems way too small to me but i don't know.

thanks to anyone who can help

Title: Re: neutralizing weak acids
Post by: AWK on October 31, 2008, 02:17:30 AM

THis is not an equilibrium problem, but a simple stoichiometry.
Write down a balanced neutralization reaction first.

Title: Re: neutralizing weak acids
Post by: Julie Smith on October 31, 2008, 03:57:47 AM

oh ok so would it just be the formula N1V1=N2V2

so (0.1M acetic acid)(10mL acetic acid)/(0.1M NaOH)=10mL NaOH?

Title: Re: neutralizing weak acids
Post by: AWK on October 31, 2008, 04:58:01 AM

Result is OK, but you can use this formula after finding the stoichiometry of acetic acid to NaOH is 1:1