What is the normality of the acid?

Question

Can someone help me answer this question, with explanations?

400ml of 2.0 normal base solution is neutralized by 80ml of acid. What is the normality of the acid?

Answer 1

400*2.0/80 = 10.0 N

Answer 2

   when an acid and base undergo a neutralization reaction  this simply means that all the meqs of acid completely react with the meqs of base present...  ( there will be no excess acid or base )  This means that at this "endpoint" the meqs of acid = meq base

a meq is 1/1000 of an equivalent which is defines as that amount of a compound that will produce or react with 1 gram formula weight of hydrogen ion...my defintion    normality = eq/Liter or meq/mL

so if the meq of acid = meq of base in a neutralization then

(mL acid)( Nacid ) = (mL base )(Nbase)

so N acid = {(mL Base )(Nbase)}/mL acid  so

(400mL )( 2 N )/80mL = 10 N   The acid is 10 N

Answer 3

Normality describes the number of protons or hydroxide ions in a solution.  It is a function of the acid or base as well as the concentration thereof.  For example, HCl has one proton available for release to the solution for each molecule of HCl added.  So the molar concentration and the normal concentration will always be the same.  This is also the case with NaOH, HNO3, etc.  H2SO4, however, has 2 protons available for release for each molecule of H2SO4, so the normal concentration of this acid is twice that of the molar concentration (2 M H2SO4 is 4 N).

Keeping this in mind, you have 400 mL of a 2 N base.  So you have 0.8 moles of hydroxide ions in the solution (.4 L * 2 mol/L).  You need an equal number of protons to neutralized the hydroxide ions.  80 mL of your acid thus contains 0.8 moles of protons, as the problem says the solution was neutralized.  So you put the 0.8 moles over the 80 mL (moles/liter), giving you a 10 Molar solution.  And because you are measuring protons, it is also a 10 Normal solution.