(i) The pH of HCl is between 0 and 2.
(ii) the presence of Carbon Dioxide turns lime water milky or sees a white precipitate form on the surface of the lime water. Lime water is CaOH and when it reacts with Carbon Dioxide it forms a white solid (precipitate) Calcium Carbonate.
[tex]Ca(OH)_{2} _{(l)} + CO_{2} _{(g)} -----\ \textgreater \ CaCO_{3} _{(s)} + H_{2}O_{(l)} [/tex]
