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

## Step 1<br />This problem is about the disposal of different types of materials used in a laboratory setting. The options given are oil used to prepare a heating bath, reaction products, excess of reagents, and none of them.<br /><br />## Step 2<br />The first option, oil used to prepare a heating bath, is a material that can be safely disposed of down the sink. This is because oil is a non-biodegradable substance that does not pose a threat to the environment when disposed of in this manner.<br /><br />## Step 3<br />The second option, reaction products, is not a suitable candidate for disposal down the sink. This is because reaction products can vary greatly in their chemical composition and some may be hazardous or toxic. Therefore, they should be disposed of according to the specific guidelines for their particular chemical composition.<br /><br />## Step 4<br />The third option, excess of reagents, is also not suitable for disposal down the sink. Similar to reaction products, excess reagents can be hazardous or toxic and should be disposed of according to specific guidelines.<br /><br />## Step 5<br />The last option, none of them, is not correct because oil used to prepare a heating bath can indeed be disposed of down the sink.