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A solution is 0.30 m in nh3. what concentration of nh4cl would be required to achieve a buffer solution with a final ph of 9.0? recall the hh equation can be written using ph and pka or poh and pkb. the kb of nh3 is 1.8 x 10–5.

Respuesta :

superman1987
- first, we have to get POH. 
and when we have PH = 9 so,
PH+POH = 14
POH = 14 -9 = 5 
- then by using this formula of PKa:
PKa = -㏒Kb and when we have Kb = 1.8x10^-5 so by substitution:
PKa   = - ㏒ 1.8x10^-5
∴PKa = 4.7
So know we have Pka & POH So by substitution in the following formula w can get the concentration:
POH = Pka + ㏒[HB]/[B}
5 = 4.7 + ㏒[HB]/[0.3]

∴[HB](NH4Cl) =0.599 m

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