Question

Which is odd term.
Gold, silver, copper, brass.
Hydrogen, hydrogen peroxide, carbon dioxide, water vapour.
Milk, lemon juice, carbon, steel.
Water, Mercury, bromine, petrol.
Sugar, salt, baking soda, blue vitriol.
Hydrogen, sodium, potassium, carbon

Answer 1

brass, water vapor, milk, water, blue vitriol

Answer 2

Brass
Co2
Steel
Water
Blue vitriol
Potassium