Properties of halogens
Boiling point - The boiling point increses as you gp down groop, this is because of increasing vander vaals forces as the relative mass of atoms icreases. this is seen in the trend of physical state of atoms.
Electronegativity - larger atoms share electrons less than smaller ones so electronegativity decreases.
a halogen will displace a halide from solution if it is below it in the periodic table.
Add chlorine gas with sodium hydoxide at room temperature you get sodium chlorate solution. NaClO(aq) also known as common household bleach. Some of the chlorine is oxided and reduced. This is known as disproportionation reaction.
Chlorine and Water
Another dispropportionation reaction
End up with a mixture of hydrochloric acide and chloric(I) acid
Chlorate(I) ions kills bacteria, therefore makes water safe to drink
kills disease causing micro organisms
prevents growth of algae
removes dis colouration caused by organic compunds
However harmful when breathed in.
irritates the respiratory system