Is calcium hydroxide or potassium hydroxide more efficient at removing carbon dioxide? In biology, we commonly use $\ce{KOH}$ in respirometers to remove carbon dioxide. A common test in chemistry to detect the presence of carbon dioxide is to bubble it through limewater, turning it milky. This has led me to wonder which is more efficient in removing carbon dioxide—$\ce{KOH}$ or $\ce{Ca(OH)_2}$—when both solutions are sitting in the atmosphere (i.e. they’re just passively absorbing $\ce{CO_2}$ and $\ce{CO_2}$ is not bubbled through either solution). An explanation would be much appreciated.
$\ce{KOH}$ (and $\ce{NaOH}$) absorb $\ce{CO2}$ more quickly and completely than $\ce{Ca(OH)2}$, but they are much more dangerous to work with: caustic to skin, deliquescent (forming a highly concentrated solution that can pour out of the apparatus), etc. For that reason, "lime water" is preferred for classroom use to demonstrate the presence of $\ce{CO2}$.