Question

Which of the following are physical rather than chemical properties of hydrogen gas (H2)? Choose one or more:
A. Liquefied H2 boils at a very low temperature (–253.7°C).
B. H2 gas does not conduct electricity.
C. At room temperature, its density is less than that of any other gas.
D. It reacts vigorously with oxygen (O2) to form water.

Answer 1

Answer: A. Liquefied $H_2$ boils at a very low temperature (–253.7°C).

B. $H_2$ gas does not conduct electricity.

C. At room temperature, its density is less than that of any other gas.

Explanation:

Chemical property is defined as the property of a substance which is observed during a reaction where the chemical composition identity of the substance gets changed.

Example: $H_2$ reacts vigorously with oxygen $O_2$ to form water. $2H_2+O_2\rightarrow 2H_2O$

Physical property is defined as the property which can be measured and whose value describes the state of physical system. For Example: State, density etc.

Example: Liquefied $H_2$ boils at a very low temperature (–253.7°C).It only changes state.

$H_2$ gas does not conduct electricity.It is only about movement of electrons.

At room temperature, $H_2$ density is less than that of any other gas. It is only about mass present per unit volume.