Which of these designates a gas at room temperature?

A) HCl(g)
B) Br2(l)/alcohol
C) C12H22O11(aq)
D) Cl2(g)/CCl4(l)

1 Answer
Jan 14, 2017

HCl(g), as HCl is naturally a gas at room temperature and pressure. It boils below room temperature, at 85.05C.

The way you can figure out what you're looking at is by looking at what is in parentheses:

  • (g)=gas
  • (l)=liquid, or very concentrated (high mol soluteL solution)
  • (s)=solid, or precipitate if within a reaction

The above are all phases, though (l) can indicate a concentrated solution.


Anything else specifies a solvent that the solute dissolves in (or a liquid that another liquid mixes with to form a liquid-liquid mixture), which is another way of saying that it is a solution:

B) specifies bromine liquid (Br2(l)) dissolved in liquid alcohol (bromine is a liquid at room temperature and pressure). An alcohol can be anything containing only C connected to H (a hydrocarbon end), and OH (a hydroxyl group), such as ethanol and butanol.

C) is sucrose (common sugar, C11H22O11) dissolved in water. (aq) denotes an aqueous solution, which is by definition something dissolved in water.

D) is chlorine gas (Cl2(g)) dissolved in carbon tetrachloride liquid (CCl4(l)). Chlorine is a gas at room temperature (check that its boiling point is less than 25C), while CCl4 has a boiling point higher than 25C.