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- Jul 16, 2009

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Please correct me if I am wrong, as I am, not sure I am headed down the right path.

So with HCL, (M) Molarity and (N) Normality are the same?

So I can use simple math for dilution?

C1V1=C2V2

If I start with 1

*M*HCL and want 1000

*mL*of HCL at 0.1

*M*

1.0

*M*× V1 = 0.1

*M*× 1000

*mL*

Solve for V1

V1 = 0.1

*M*× 1000

*mL*/ 1.0

*M*

SO

V1 = 100

*mL o*f 1

*M*HCL

Equipment Needed

1000

*mL*Class A volumetric flask

100

*mL*Class A volumetric flask (or volumetric pipette)

Procedure

1 - Fill 100

*mL*flask to line (bottom of meniscus) with 1

*M*HCL

2 - Add roughly 750

*mL*of lab grade distilled water to 1000

*mL*flask

3 - Slowly add the measured 100

*mL*of 1

*M*HCL to the partially full 1000

*mL*flask

4 - Swirl to mix (or stopper and invert?)

5 - Fill 1000

*mL*flask to line.

6 - Stopper and invert 25 times (is that overkill?)

Accuracy

Assuming the beginning solution is actually 1

*M*and the water is lab grade, and both flasks are "Class A" and within their stated accuracy.

(Let's ignore me being able to hit the line precisely)

I read the tolerances of class A to be

100

*mL*Flask Tolerance: ±0.08

*mL*

1000

*mL*Flask Tolerance: ±0.30

*mL*

For the 100

*ml*flask that means an actual volume (excluding my precision) of

V

*1min*= 100

*mL*− 0.08

*mL*= 99.92

*mL*

V

*1max*= 100

*mL*+ 0.08

*mL*= 100.08

*mL*

For the 1000

*ml*flask that means an actual final volume of (excluding my precision) of

V

*2min*= 1000

*mL*− 0.30

*mL*= 999.7

*mL*

V

*2max*= 1000

*mL*+ 0.30

*mL*= 1000.3

*mL*

Calculation of final possible concentrations of my dilution using the equipment above and ignoring any precision error introduced by me:

C

*fmin*= 1.0

*M*× 99.92

*mL*/ 1000.3

*mL*= 0.09992

*M*

C

*fmax*= 1.0

*M*× 100.08

*mL*/ 999.7

*mL*= 0.10008

*M*

So a final acid concentration somewhere between 0.09992

*M*and 0.10008

*M ??*

In the real world (if I even remotely did that right) what would the final range (±) look like with the human element of precision added in reading the flask and/or other issues (a drop or two left in the 100 ml etc. ??

Sorry if this is basic or silly. In the end I want to know if reducing 1

*M*HCL to 0.1

*M*(

*N*?) for use as a KH reagent (titration) is reasonable or will introduce too much error to be worth the trouble.