$\text{Cl}_2 + 2\text{H}_2\text{O} + \text{SO}_2 \longrightarrow 4\text{H}^+ + \text{SO}_4^{2-} + 2\text{Cl}^-$

$\text{Cu}^{2+} + \text{Zn} \longrightarrow \text{Cu} + \text{Zn}^{2+}$

$2\text{H}_2 + \text{O}_2 \longrightarrow 2\text{H}_2\text{O}$

$\text{HCl} + \text{H}_2\text{O} \longrightarrow \text{H}_3\text{O}^+ + \text{Cl}^-$

Cristobalite

$\alpha$ - quartz

$\beta$ - quartz

Aragonite

Chloroethyne

3 - Chloropropyne

1 - Chloropent - 2 - yne

4 - Chloropent - 2 - yne

Each member of a series has same functional group.

Each member has same type of carbon skeleton.

Each member differs by ethylene group from next member.

All members of series possess similar chemical properties.