solubility of NaOH

Checking the boiling point of NaOH solutions.

Placed in an erlen (52.31 g tare) 5 g NaOH(H2O)x, flakes, and 10.4 g H2O.

Re-weighted when boiling at 112 C: 12.23 g.  

Added H2O to 15.20 g. 

Re-weighted when boiling at 120 C: 11.79 g.

Re-weighted when boiling at 130 C: 9.47 g.

Poured off on metal dish (T1)

------

Discarded (S1) minus sodium aluminate(?) crust (S4).

Dissorved (S4) in hot water. 

Poured some (T1) on aluminum foil. Kept adding while bubbling.  Added (S4) too.

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unknown date
sodium phosphates

NaH2PO4  
  d 2.36 g/mL  sol 59.9 g/dL

Na2HPO4  
  hydrates 2, 7, 8, 12
  pH 8-11
  d 1.7 g/mL
  MP 250 C dec
  sol heptahydrate 7.7 g/dL at 20 C
  sol heptahydrate 18.8 g/dL at 25 C
  insol ethanol
  
Na3PO4 
 orthorombic
 used for cleaning
 pH 1%: 12
 dissolves copper oxide at high temperature
 MP 1583 C
 d anhydrous 2.536 g/mL
 insol ether
 sol water anydrous g/dL:
     0 C  5.4 
    20 C  12
    25 C  14.5
    40 C  23.3
   100 C  94.6
 dodecahydrate: MP 73.4 C  BP 100 C
 
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unknown date
ammonium phosphates

NH4H2PO4  
 sol ether
 d 1.80 g/mL
 MP 180 C
 sol water 40.4 g/dL at 25C
 
(NH4)2HPO4
 starts decomp emitting NH3 at 70 C
 avg pH 7.5-8
 insol ether
 sol water g/dL:
   10 C  57.5
  100 C 106.7  
 MP 155 (decomp)
 d 1.619 g/mL
 
(NH3)3PO4
  unstable, no commercial value.

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Solubility data of NH4H2PO4 from various sources. 
Some may be hydrated?

Date: 1920
mass fractions
 0 C  0.300
10 C  0.384
20 C  0.408
30 C  0.425
40 C  0.450
50 C  0.470
60 C  0.494
70 C  0.514

Date: 1936
mass fractions
192 C 0.832
182 C 0.820
161 C 0.730
126 C 0.649
120 C 0.622

Date: 1947
mass fractions
 0.0 C  0.304
 4.0 C  0.320
 8.4 C  0.340
10.6 C  0.352
12.2 C  0.360
15.8 C  0.384
16.5 C  0.390
26.0 C  0.404

Date: 1967
mass fraction

 -4.5 C  0.180 (?)
 -4.0 C  0.170
 -2.0 C  0.100 (?)
 -1.6 C  0.190
 +2.5 C  0.200
 +9.5 C  0.225
+22.5 C  0.275
+32.5 C  0.325
+35.5 C  0.340
+39.0 C  0.350
+46.5 C  0.375
+51.5 C  0.400

Date: 1973
mass fraction
 -4.3 C  0.169 (eutectic)

Date: 1911
mass fraction
  0 C  0.198
 25 C  0.300
 25 C  0.290   (?)
 50 C  0.410
 70 C  0.492
 83 C  0.566
 
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