Gen. Chem question

[Erhatstil]

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Acid-Base titration question

what volume of HCl was added if 20ml of 1M NaOH is titrated with 1M HCl to produce pH=2.

so i know 20ml HCl will neutralize and we need a final [H+]=1.0x10^-2 in soln. the final volume will be 40ml plus something. is it just (.01)(x+40ml)? this will give x=.4ml. but this doesn't seem like very much extra HCl added.

 

[UndergradGuy7]

Acid-Base titration question

what volume of HCl was added if 20ml of 1M NaOH is titrated with 1M HCl to produce pH=2.

so i know 20ml HCl will neutralize and we need a final [H+]=1.0x10^-2 in soln. the final volume will be 40ml plus something. is it just (.01)(x+40ml)? this will give x=.4ml. but this doesn't seem like very much extra HCl added.

Looks good to me. We know 20 mL of HCl are needed to make the solution neutral. Then you want to figure out how many milliliters are needed to make it a ph of 2.

So m1v1=m2v2
(1M HCl)(x milliliters) = (0.01 M of H+)(40+x milliliters)
solve for x and you get 0.4 mL
So we need 20 + 0.4 = 20.4 millilters