|From:||Connie McManus <firstname.lastname@example.org>|
The same principle applies here as with NaOH except you factor in the
specific gravity and the concentration.
the formulas is: g-eq/H ions x specific grav x conc (converted to a
1) Find the gram eq of HCl by adding the atomic weights of HCl: H (1) +
Cl (35.5) = 36.5. Notice that this is the same as the Formula Weight
(FW) or molecular weight.
2) HCl dissociates in solution to H+ and Cl- ions -- there is only 1
Hydrogen ion/mole --
3) Factor in the specific gravity and the Concentration (found on the
bottle of concentrated acid). From my own bottle of HCl I get, sp g =
1.18 and conc = 36%. Convert the 36% to a decimal (0.36) and multiply
them with the number of H ions:
g-eq HCl / H x sp g x conc = 36.5/1 x 1.18 x 0.36 = 85.92 mL
4) Add 85.92 mL conc HCl to 914.08 ml water = 1N solution of HCl.
5) You can easily dilute this down to make the 0.2N solution you need by
making a 1:20 dilution (that is, 1 part 1N HCl and 19 parts water).
6)You probably already know this, but always add ACID to WATER (slowly)
when preparing these solutions!!
It gets trickier when you have a compound with more than 1 H/mole to
donate to the solution, such as sulfuric acid (H2SO4). But in this
case, there are 2 H ions, to plug into the formula.
i love chemistry!!
Connie McManus... Happy TGIF everyone!!!!
"Erhiaganoma, Kemi" wrote:
> Whilst on the subject of Normality, could anyone pls tell me (or remind me)
> on how to make up 0.2N HCl solution. Does specific gravity matter when it's
> a liquid involved?
> Thanks, Kemi
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