Tuesday

January 27, 2015

January 27, 2015

Posted by **AAA** on Monday, August 6, 2012 at 7:49am.

- Chemistry -
**DrRuss**, Monday, August 6, 2012 at 8:02amI have a 40 ml solution of pH 4.36. I need to make this solution at pH 8.5 by adding extra 10 ml of HCl and NaOH.

Not sure that this question entirley makes sense. However,

if pH is 4.36 then pOH is 9.74 and [OH-] is 1.82 x 10^-10 M

if target pOH is 5.5 then [OH-] is 3.16 x 10^-6

so total number of milli moles of OH- in target solution is

50 x 3.16 x 10^-6 mmoles

and we have

40 x 1.82 x 10^-10 mmoles

so we need the difference which is

(50 x 3.16 x 10^-6 mmoles)-(40 x 1.82 x 10^-10 mmoles)

which is ca 50 x 3.16 x 10^-6 mmoles

=0.000158 mmoles in 10 ml so the concentration is

1.58 x 10-5 M of NaOH solution.

Please check the maths!

**Answer this Question**

**Related Questions**

Chemistry - You have an unlimited amount of 12M HCl stock solution. You need to ...

Chemistry - You have an unlimited amount of 12M HCl stock solution. You need to ...

Science - How much sodium hydroxide, at what concentration, do I need to add to ...

Chemistry - Imagine that you are in chemistry lab and need to make 1.00 L of a ...

Chemistry - A 50mL solution of NaOH is neutralized by adding 37.5 mL of 0.045 M ...

ap chemistry - please explain titration problems. I'm a total noob at this and ...

chemistry- some help plzz totally lost on this one - Imagine that you are in ...

Chemistry Help! Thank you :) - Assuming the final solution will be diluted to 1....

Chemistry - Calculate the concentration, in molarity, of a solution prepared by ...

CHEM HELPP!!! - Imagine that you are in chemistry lab and need to make 1.00 of a...