# Why is chloroform kept in dark coloured bottles?

Why is chloroform ($\ce{CHCl3}$) kept in dark coloured bottles?

• I'm voting to close this question as off-topic because the answer is quite easily found by typing "why is chloroform kept in dark bottles" into the Google search box. – Todd Minehardt Aug 21 '16 at 18:54
• @Todd lack of research on itself isn't a close reason. You can down vote instead. – M.A.R. Aug 21 '16 at 22:26
• @DEAD - My bad. VTC retracted. Thanks for the procedural reminder! – Todd Minehardt Aug 21 '16 at 22:27
• good point @DEAD – szentsas Aug 21 '16 at 23:03

In the presence of UV light, chloroform can be oxidized by atmospheric oxygen to phosgene ($\ce{COCl2}$), a toxic gas. The dark colored glass blocks UV light so that phosgene is not produced.