How to produce a constant moisture in a closed container

 

Water solution

FORMULA

% Relative moisture at 20°C

di sodium hydrogen phosphate

Na2 HPO4 – 12 H2O

95

Sodium carbonate

Na2CO3 – 10 H2O

92

Zinc sulfate

ZnSO4 – 7 H2O

90

Potassium chloride

KCl

86

Ammonium sulfate

(NH4)2 SO4

80

Sodium chloride

NaCl

76

Sodium nitrite

NaNO2

65

Ammonium nitrate

NH4NO3

63

Calcium nitrate

Ca (NO3)2 – 4H2O

55

Potassium carbonate

K2CO3

45

Zinc nitrate

Zn (NO3)2 – 6H2O

42

Calcium chloride

CaCl2 -  6H2O

32

Lithium chloride

LiCl – H2O

15