Question

What is the final product when oxygen and hydrogen are mixed in a test tube at room temperature?

• A. Hydrogen peroxide
• B. Water
• C. A base
• D. A zwitterion
• E. No reaction takes place

Answer 1

The correct option is E No reaction takes place

The gas-phase oxidation of hydrogen has been extensively studied over a wide range of temperatures and pressures.

$H_2+\frac{1}{2}{O}_2\to H_{2}O$ ,$\Delta H^o=-242kj/mol$
$H_2\left(g\right)+\frac{1}{2}{O}_2\left(g\right)\to H_{2}O\left(g\right)$ $\Delta H^o=–242kJ/mol$

This reaction does not take place at all when the two gases are simply mixed at room temperature.

At temperatures around 500-600°C it proceeds quite smoothly, but when heated above 700° or ignited with a spark, the mixture explodes.

Hence the correct option is E.