Question

lesson 42-classification of materials
how does hydrogen react in a flame test?
(1 point)
changes color
nothing happens
a pop
puts flame out

Explanation:

In a flame test for hydrogen, when a burning splint is introduced to hydrogen gas, a reaction occurs. Hydrogen gas is highly flammable. The reaction of hydrogen with oxygen in the air (when ignited) is \(2H_2 + O_2
ightarrow 2H_2O\). This reaction is rapid and produces a small explosion - like sound, which is heard as a "pop" sound.

• Option "changes color": Hydrogen itself does not have a characteristic color - changing property in a simple flame test like some metal ions (e.g., copper gives a green - blue color in a flame test).
• Option "nothing happens": Hydrogen is reactive in the presence of a flame (as it can react with oxygen).
• Option "puts flame out": Hydrogen is a fuel (combustible), not a fire - extinguisher. It does not put out the flame but rather reacts with the oxygen in the flame (if present in a combustible mixture).

Answer:

a pop