Table 7. Experimental Values of Solubility and Dry Salt of the Quaternary System NaOH–Na₂CO₃–Na₂SO₄–H₂O at T = 363.15 K and P = 88.94 kPa^a.

	liquid mass, w(B) × 100b, %				dry salt (liquid) mass, w(B) × 100b, %
no.	NaOH	Na2CO3	Na2SO4	H2O	NaOH	Na2CO3	Na2SO4	H2O mass (g/100 g dry salt)	solution density ρ/g·cm–3	equilibrium phase solidsb
1	0.00	0.00	29.91	70.09	0.00	0.00	100.00	234.34	1.1984	S
2	34.18	2.22	0.00	63.60	93.90	6.10	0.00	174.73	1.3321	S1 + S
3	71.62	2.75	0.00	25.63	96.30	3.70	0.00	34.46	1.5885	S1 + OH
4	76.28	0.00	0.00	23.72	100.00	0.00	0.00	31.10	1.5884	OH
5	48.79	0.55	0.00	50.66	98.88	1.12	0.00	102.68	1.4696	C + OH
6	17.14	10.99	0.00	71.87	60.93	39.07	0.00	255.49	1.2339	C + C1
7	0.00	30.50	0.00	69.50	0.00	100.00	0.00	227.87	1.3112	C1
8	0.00	20.65	6.40	72.95	0.00	76.34	23.66	269.69	1.2557	C1 + γ
9	0.00	4.41	25.99	69.60	0.00	14.51	85.49	228.95	1.2248	S + γ
10	3.85	3.60	23.08	69.47	12.61	11.79	75.60	227.49	1.1948	S + γ
11	8.81	2.96	19.79	68.44	27.92	9.37	62.71	216.80	1.2193	S + γ
12	12.07	3.54	17.23	67.16	36.93	10.78	52.29	203.66	1.2186	S + γ
13	21.89	2.29	10.22	65.60	63.64	6.66	29.70	190.66	1.2574	S + γ
14(E1)	27.03	2.29	6.61	64.07	75.23	6.37	18.40	178.38	1.2869	S + γ + S1
15(E2)	55.85	2.09	1.69	40.37	93.66	3.51	2.83	67.71	1.5477	OH + S1 + γ
16(E3)	51.66	2.86	0.84	44.64	93.32	5.16	1.52	80.66	1.5102	C1 + C + OH
17(E4)	61.85	4.89	1.78	31.48	90.27	7.14	2.59	45.94	1.5885	OH + C1 + γ
18	21.55	5.08	2.25	71.12	74.62	17.58	7.80	246.24	1.2525	C1 + γ
19	11.80	13.16	4.28	70.76	40.36	45.00	14.64	242.08	1.2192	C1 + γ
20	10.64	13.86	4.54	70.96	36.65	47.72	15.63	244.39	1.2203	C1 + γ
21	8.64	15.02	5.05	71.29	30.10	52.32	17.58	248.29	1.2216	C1 + γ

^aStandard uncertainties u are u(T) = 0.1 K, u(P) = 0.5 kPa, and u_r(Na₂CO₃) = u_r(Na₂SO₄) = u_r(NaOH) = 0.05.

^bAbbreviations: S, Na₂SO₄; OH, NaOH; C₁, Na₂CO₃·H₂O; S1, Na₂SO₄·NaOH; and γ, mNa₂SO₄·nNa₂CO₃.