For pipettes marked with To Deliver (TD), the remaining liquid on the tip should be blown out.

• A. True
• B. False
• C. Not applicable
• D. Sometimes

Answer: (B)

The important idea here is how TD (to deliver) pipettes handle the liquid left in the tip. Different pipettes are designed so that the amount delivered to the receiving vessel matches the nominal volume, but the method for ensuring that last bit of liquid is expelled isn’t identical across all models. Some TD pipettes require blowing out the final drop to guarantee the full volume is delivered, while other TD models are calibrated so that delivering the volume does not depend on blowing out the last drop, meaning the residual liquid in the tip isn’t counted or isn’t blown out. Because this behavior can vary by manufacturer and specific instrument, you can’t say universally that the remaining liquid on the tip should always be blown out for TD pipettes. That’s why the statement is false in general: always follow the pipette’s manual or labeling to know whether blowing out is required for your device.