The Odd One Out: Chemistry Style Quiz

Answer: Iodine

All the others consist of more than one chemical element! Dry ice is the solid state of carbon dioxide (CO2).

Answer: Ammonia

The aqueous solutions of the three wrong answers are acidic (pH value below 7), whereas aqueous ammonia is basic (pH above 7).

Answer: Benzene

In spite of its name ending in -ene, benzene is not an alkene (a compound with a double carbon-carbon bond), but rather an aromatic compound consisting of a 6-membered aromatic ring.

Answer: Toluene

All the other answers describe the same compound - C6H5CH(CH3)2. Toluene is also known as methylbenzene or, less commonly, phenylmethane and has the chemical formula C6H5CH3.

Answer: Magnesium sulphate

While MgSO4, also known as Epsom salt, tastes bitter, the other three choices taste sweet. But careful - lead compounds are toxic! Apparently, ancient Romans used Pb(CH3COO)2 to sweeten their wine! Definitely not healthy...

Answer: Methylamine

The wrong choices are all explosives - some more commonly known, like trinitrotoluene (TNT) and glyceryl trinitrate (Nitroglycerine), others - like octanitrocubane - recently synthesised. Methylamine, while highly flammable, is not a high explosive. It is used as an intermediate product in organic chemistry.

Answer: Sulphuric acid

Even though some films, especially cartoons, tend to depict acids as neon green, your typical acid is colourless! The wrong answers are all organic dyes. Beta-carotene gives carrots their colour, chlorophyll is the green in plant leaves. Fluorescein is a synthetic compound which, as the name suggests, is a fluorescent dye.

Answer: Tristearin

You can try this one out in the kitchen! Tristearin (a type of saturated fat) doesn't dissolve in water. Ethanol (the alcohol found in beverages - bet you knew this one!), acetic acid (the acid in vinegar) and NaCl (table salt) are all water soluble.

Answer: Hydrogen

Hydrogen is the only reducing agent among the four - the rest are all oxidizing agents.

Answer: Dihydrogen monoxide

The symbols s, l and g are used to denote solid, liquid and gaseous state. Dihydrogen monoxide is a fancy name for plain water! Under standard pressure at room temperature water is liquid, the other three oxides are gasses.
The scientific name of water was used to create a joke website about the dangers of "DHMO" (www.dhmo.org) - really funny when you know what they're talking about! Speaking of fun, N2O is known as "laughing gas". As for dangerous, CO2 (a greenhouse gas) and SO2 (responsible for acid rain) are far more dangerous than DHMO!