Normality Question

[Smooth Operater]

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what is the normality of a 1 M solution of H3PO4 if titrated with CaCl2?

The answer is 1.5 N, but can anyone explain why?? Thanks!

 

[Uracil]

I think is because (1M)(3) / (2)

1*3 because there are 3 hydrogen ions
2 because there are 2 Cl ions

im not sure if Im doing it right.

 

[Smooth Operater]

yeah, i wonder how would you explain the logic behind that. Does it take 2 Cl- to neutralized 3 H + ?

 

[doc toothache]

There are 3 available hydrogens but only 2 are used in the reaction.

 

[dudewhensmydat]

what is the normality of a 1 M solution of H3PO4 if titrated with CaCl2?

The answer is 1.5 N, but can anyone explain why?? Thanks!

I dunno why it's 1.5N; BUT...i can tell you that i read somewhere that Normality is always greater than Molarity (numerically speaking), so atleast we're on the right track here.

 

[gijohn529]

so you have 1M of H3 which means you have 3 moles. The calcium chloride you have 2 cl's per mole so the normality is 1.5 N of calcium chloride which then gives you 3 moles of cl.

 

[Smooth Operater]

mmm, is there a formula to calculate normality given molarity?

is it M*mole = N ?

 

[erichen]

im not too sure since im not even in college yet...only AP chem background

but since there are 3 Hydrogens and 2 Chlorines, you can think of it as normality= the number of hypothetical anions to titrate the hydrogens.

since since 1.5 x 2 chlorines = -3 would theoretically titrate 3 hydrogens = +3, it cancels out.

 

[denteng]

I wouldn't worry too much about normality. I only had 1 question where it was required.

Just think of is as: N = (moles/L) (# of active particles in compound)

ie. H2SO4 is 2, HCL is 1. When it's a redox reaction, the moles of electrons involved are your #.

Hope it helps.

im not too sure since im not even in college yet...only AP chem background

but since there are 3 Hydrogens and 2 Chlorines, you can think of it as normality= the number of hypothetical anions to titrate the hydrogens.

since since 1.5 x 2 chlorines = -3 would theoretically titrate 3 hydrogens = +3, it cancels out.

 

[denteng]

BUT...i can tell you that i read somewhere that Normality is always greater than Molarity (numerically speaking)

Minor correction: Equal or greater. Not greater than.