Determine the pH (to two decimal places) of the solution that is produced by mixing 319 mL of 6.01×10-4 M HBr with 535 mL of 4.51×10-3 M HCl?

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Answer 1 · 2017-11-19T17:19:04

pH = 2.52

We need to find the total no. of moles of #sf(H^+)# ions then find the concentration. This will give us the pH.

#sf(c=n/v)#

#:.##sf(n=cxxv)#

#:.##sf(n_(HBr)=6.01xx10^(-4)xx319/1000=1.9172xx10^(-4))#

Note I have divided the volume by 1000 as we need to work in Litres.

#sf(n_(HCl)=cxxv=4.51xx10^(-3)xx535/1000=24.12xx10^(-4))#

Since both HCl and HBr dissociate completely we can say that the total moles of #sf(H^+)# is given by:

#sf(n_(H^+) =(24.1285+1.9172)xx10^(-4)=26.0457xx10^(-4))#

#sf(c=n/v)#

#:.##sf([H^+]=(26.0457xx10^(-4))/(((319+535))/(1000))=3.04985xx10^(-3)color(white)(x)"mol/l")#

#sf(pH=-log[H^+]=-log[3.04985xx10^(-3)]=2.52)#