How can HCl be liquid if it has a boiling point at -85°C?
All halogen compounds with hydrogen ($\ce{HX}$) are gases at STP except for $\ce{HF}$, which is a liquid (b.p.: $\mathrm{19~^\circ C}$). When dissolved in water, $\ce{HX}$ dissociates to ions ($\ce{H+}$ &amp; $\ce{X-}$), which are readily hydrated by water molecules as $\ce{H+ (aq)}$ and $\ce{X- (aq)}$, hence not exists as a gas any more.

To answer your side question, a lot of gases have this feature. For instance, sulfur trioxide ($\ce{SO3}$) is a gas but gives sulfuric acid ($\ce{H2SO4}$) when it come to contact with water. Similarly, nitric acid ($\ce{HNO3}$) can be considered as an aqueous solution of nitrogen dioxide ($\ce{NO2}$). In reality, during an industrial process, $\ce{NO2}$ react with $\ce{H2O}$ in air to give $\ce{HNO3}$.
$$\ce{4NO2(g) + O2(g) + 2H2O(l) -&gt; 4HNO3 (aq)}$$
Exception to this trend is carbonic acid ($\ce{H2CO3}$), which decomposes under ambient conditions:
$$\ce{H2CO3(aq) -&gt; CO2(g) + H2O(l)}$$