1)Calculate the pH of a 0.1M solution of NaOH ,knowing that the volume of the solution is 300mL. 2)Calculate the pH of a 0.3M solution of HCl , knowing that the volume of the solution is 250mL (?)

1 Answer
May 24, 2017

Answer:

We use the relationship.........#pH+pOH=14#............in aqueous solution under standard conditions............

Explanation:

#(i)#.........#pH+pOH=14#............ and by definition, #pH=-log_10[H_3O^+]#, and #pOH=-log_10[HO^-]#.

For a #0.1*mol*L^-1# solution of #NaOH#, we KNOW (do we?) that #HO^(-)-=0.1*mol*L^-1#, and thus #pOH=-log_10(0.1)=-(-1)=1#.

And given #pH+pOH=14#, #pH=14-pOH=14-1=13#. The volume of the solution is irrelevant here.

#(ii)#.........#pH=-log_10[H_3O^+]=-log_10(0.300)=0.523#. Again the volume of the solution is a distractor............