Posted by Korina on Tuesday, December 14, 2010 at 7:55pm.
A laboratory technician is required to prepare a quarter normal saline solution (0.22% w/v) from the stock normal saline solution.
1. What is the dilution factor required?
I have 4fold dilution  is that correct?
2. Ise this dilution factor to calculate the volume of stock needed if one litre of the diluted solution is to be prepared.
I have 0.22 over (divided by) 0.91 = 0.2417582  is that correct? And how do I then convert it into a fraction in its lowest form?
Thanks.

Chemistry  DrBob222, Tuesday, December 14, 2010 at 8:25pm
I don't know how accurately you want this done but I would think a quarter normal solution would be 0.91/4 = 0.2275 in which case 4fold dilution is needed.
2. I don't think it is needed.
If we use M x mL = M x mL, then
0.91/100 x mL = 0.2275/100 x 1,000
mL = 0.2275*1000/0.91 = 250. mL. 
Chemistry  Korina, Wednesday, December 15, 2010 at 1:58am
Hi DrBob222,
Thanks for your help.
:)