Which can be discarded to sink? Select one: a. Excess of reagents b. None of them c. Oil used to prepare a heating bath d. Reaction products

## Step 1<br />This problem is about understanding the principles of laboratory safety and waste disposal. In a laboratory setting, it is crucial to know which materials can be safely discarded down the sink.<br /><br />## Step 2<br />Option a, "Excess of reagents", refers to the chemicals used in reactions. These chemicals can be hazardous and should not be discarded down the sink unless they are harmless and non-toxic. <br /><br />## Step 3<br />Option b, "None of them", suggests that none of the listed items can be discarded down the sink. This is not necessarily true, as some of the items listed may be safe to dispose of in this manner.<br /><br />## Step 4<br />Option c, "Oil used to prepare a heating bath", is a non-reactive substance that does not pose a threat to the environment if disposed of in the sink. Therefore, it is generally safe to discard oil used in a heating bath down the sink.<br /><br />## Step 5<br />Option d, "Reaction products", refers to the substances formed as a result of chemical reactions. These substances can vary in their properties and may be hazardous. It is essential to follow specific disposal guidelines for reaction products, which often involve neutralization or other treatment methods to ensure they are not harmful before disposal.<br /><br />## Step 6<br />Based on the above analysis, the most appropriate answer is option c, as oil used to prepare a heating bath is generally safe to discard down the sink.