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Lithium chloride hygroscopicity

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I want to use lithium chloride to help me calibrate some humidity sensors in a sealed box. Apparently a saturated solution of lithium chloride can keep air at a humidity of 11.3% at room temperature. My question is, if I had 30 grams of LiCl in a container that wasn't sealed, so it could keep absorbing water from the environment, am I right in thinking it would be able to absorb ~35.6 ml of water? The solubility is 84.3 g/100 ml at 25 °C so I figured 84.3 g / 30 g = 2.81 and 100 ml / 2.81 = 35.6 ml - I want to make sure it can't overfill its container and cause a spill if I can't keep it airtight.

Potassium carbonate has a solubility of 111-138 g/ml at 20 °C, depending who you ask - does that mean it will absorb more water from the air (per unit of mass), provided the humidity is high enough?

I'm also wondering whether I'd need to add any water at all to the LiCl. I plan to check what humidity I get without adding water anyway, but since it's so hygoscopic and meant to be taking water out of the air, it seems counter productive for me to waste some of its capacity by deliberately adding water (I'm 100% certain that the air I will be conditioning will start out much higher than 11%).

Also, when the time comes to regenerate my anhydrous LiCl, can I dry it at a lower temperature if I use a vacuum chamber? I read that you need up to 186 °C to drive off all the water from LiCl and I was hoping I could do it in its polypropylene bottle by just lowering the pressure. 

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