Hydrogen
gas (H2) can be found in trace amounts in Earth’s atmosphere.
a. Hydrogen is found in acids.
b. Hydrogen gas is highly flammable.
c. Hydrogen reacts with oxygen to form water.
These are true, but they all describe chemical properties
of Hydrogen, not physical properties.
d. Hydrogen gas
is less dense than oxygen gas.
Yes ! This is a physical property of Hydrogen.
