What volume, in milliliters, of 0.530 M Ca(OH)2 is needed to completely neutralize 276 mL of a 0.220 M HI solution?

1 Answer
Feb 21, 2018

This is again a question that is completely made-up...which I think is a no-no....

Explanation:

I don't think you can prepare a #Ca(OH)_2(aq)# solution whose concentration is #0.530*mol*L^-1#. For calcium hydroxide, #K_"sp"=5.5xx10^-6#, and this gives a max. solubility of approx. #0.02*mol*L^-1#. And whoever set the question needs to get his/her act together...

I propose that the solution is #0.530*mol*L^-1# in #NaOH(aq)#...the which is chemically reasonable and reacts according to the stoichiometric equation...

#NaOH(aq) + HI(aq) rarr NaI(aq) + H_2O(l)#

#"Moles of HI(aq)"=276*mLxx10^-3*L*mL^-1xx0.220*mol*L^-1=0.06072*mol#.

And we require ONE equiv of sodium hydroxide solution....as is manifestly clear from the given stoichiometry.

And so #"volume of NaOH(aq)"=(0.06072*mol)/(0.530*mol*L^-1)xx10^3*mL*L^-1=114.6*mL#

The hypothetical calcium hydroxide solution would require DOUBLE this volume.....

Now clearly I answered the question I wanted to, and not the question you asked, but the question you asked was chemically unreasonable, and should not have been proposed...tell your teacher to lift his game....