Nome: hydroquinone; quinol; benzene-1,4-diol
* IUPAC
Número CAS: 123-31-9
Fórmula química: C₆H₆O₂ or C₆H₄(OH)₂
Massa molar: 110.11064 g
Percentual de massa: C 65.447 %; H 5.4923 %; O 29.060 % 
isômeros:  2-acetylfuran

• orgânico • aromático • fenol

• "The bombardier beetle has a fascinating defense mechanism based on the oxidation of an organic compound with hydrogen peroxide. Within the beetle is a sac containing a mixture of the compound (hydroquinone) and hydrogen peroxide. An enzyme initiates the reaction, which is so exothermic that it causes the liquid to boil. The boiling liquid is then expelled at the beetle's enemies." 1

• "As photographic reducer and developer; as reagent in the determination of small quantities of phosphate; as antioxidant. Depigmentor." 2

Ponto de fusão:*
172.3°C 3 = 445.45 K = 342.14°F
Ponto de ebulição:*
287°C 3 = 560.15 K = 548.6°F
Densidade (g/cm3):
1.328 at 15°C 3
1.332 at 15°C 2
* - 1 atm pressure

qualitativo:
solúvel:  • 3
muito solúvel:  • 3

ligações duplas: 3
ligações triplas: 0
Sigma Bonds: 14
Pi Bonds: 3
Total: 17
Grupos carboxilo: 0
grupos hidroxilo: 2

The heat of combustion is the amount of heat released when one mole of a substance undergoes combustion according to the general reaction equation:
CxHyOz + 0.25(4x+y-2z) O2 (g) → x CO2 (g) + 0.5y H2O (ℓ)

ΔHcomb° (s): -682.12740917782 kcal = -2854.05 kJ
ΔHcomb° (g): -705.836778202677 kcal = -2953.25 kJ

NFPA 704 Ratings:
Health: 2 - Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury.
Flammability: 1 - Must be heated before ignition can occur. Flash point over 93°C (200°F).
Reactivity: 0 - Normally stable, even under fire exposure conditions, and is not reactive with water.

Wikipedia

(1) - Ebbing, Darrell D. General Chemistry 3rd ed.; Houghton Mifflin Company: Boston, MA, 1990; pp 536-537.
(2) - The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals, 13th ed.; Budavari, S.; O'Neil, M.J.; Smith, A.; Heckelman, P. E.; Kinneary, J. F., Eds.; Merck & Co.: Whitehouse Station, NJ, 2001; entry 4833.
(3) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 3-43.
(4) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 5-44.
(5) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 5-44.
(6) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 5-44.