Safety Blank 1 Question 3[select: , Dichloromethane, Water, Sodium hydrogen carbonate, Paracetemol, Startch] is a possible carcinogen that should be handled in the fume cupboard. When shaking the separating funnel, the tip should be facing Blank 2 Question 3[select: , towards the back of the fume cupboard, at your lab coat, at the floor, at someone's face] .

Question

BlackTom AI · Accepted Answer

Dichloromethane is a volatile chlorinated solvent and is classified as a possible carcinogen, so it must be handled in a fume cupboard. Pointing the separatory funnel tip towards the back of the fume cupboard keeps vapour and any accidental ejection away from you and others.

1) Relevant knowledge points and concepts
- Dichloromethane (DCM, methylene chloride) is a volatile organic solvent with health hazards including possible carcinogenicity and harmful inhalation effects; therefore manipulations that release vapour (pouring, shaking, venting) should occur in a fume cupboard.  
- When using a separatory (separating) funnel you must avoid pointing the spout at people; venting a funnel after shaking can expel droplets or vapour under pressure. The safe practice is to point the spout into the fume cupboard, away from personnel, and preferably toward the rear so any expelled material is contained by the hood airflow.

2) Step-by-step reasoning
- From the list (Dichloromethane, Water, Sodium hydrogen carbonate, Paracetamol, Starch), the only volatile, hazardous solvent listed is dichloromethane → choose Dichloromethane.  
- For the funnel tip direction, of the choices (towards the back of the fume cupboard, at your lab coat, at the floor, at someone's face), pointing at people or clothing is unsafe; pointing at the back of the fume cupboard directs any spray/vapour away from people and into the hood’s exhaust → choose towards the back of the fume cupboard.

3) Intermediate safety steps (practical detail)
- Hold the stopper firmly, invert the funnel with spout directed to the back of the hood, open the stopcock briefly to vent away from people, and repeat venting as pressure builds.

4) Why the correct answer is correct
- DCM’s toxicity and volatility require fume-cupboard use; pointing the tip to the back minimizes exposure risk during venting.

5) Why other options are incorrect
- Water, sodium hydrogen carbonate, paracetamol, starch are not volatile carcinogenic solvents. Pointing the tip at your lab coat, the floor, or someone’s face exposes people/clothing to ejected liquid or vapour and is unsafe.

6) Conclusion
- Therefore the correct answers are Dichloromethane and towards the back of the fume cupboard, matching the provided answer.

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