Table:
substance and its state
defining point

k
°c
°r
°f

triple point of hydrogen
13.8033
-259.3467
24.8459
-434.8241

triple point of neon
24.5561
-248.5939
44.2010
-415.4690

triple point of oxygen
54.3584
-218.7916
97.8451
-361.8249

triple point of argon
83.8058
-189.3442
150.8504
-308.8196

triple point of mercury
234.3156
-38.8344
421.7681
-37.9019

triple point of water
273.16
0.01
491.69
32.02

melting point of gallium
302.9146
29.7646
545.2463
85.5763

freezing point of indium
429.7485
156.5985
773.5473
313.8773

freezing point of tin
505.078
231.928
909.140
449.470

freezing point of zinc
692.677
419.527
1,246.819
787.149

freezing point of aluminium
933.473
660.323
1,680.251
1,220.581

freezing point of silver
1,234.93
961.78
2,222.87
1,763.20

freezing point of gold
1,337.33
1,064.18
2,407.19
1,947.52

freezing point of copper
1,357.77
1,084.62
2,443.99
1,984.32

Statement: the triple point of hydrogen's defining point is -259.3467 °c.
Question: what is the triple point of hydrogen's defining point?
Answer: -259.3467