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Difference between blow-out (serological/to deliver) pipettes and Mohr pipettes

A) Mohr pipettes are used for titrations, while blow-out pipettes are not.
B) Blow-out pipettes have a single graduation mark, while Mohr pipettes have multiple.
C) Mohr pipettes are designed for delivering precise volumes, while blow-out pipettes are for general use.
D) Blow-out pipettes have a larger bore size compared to Mohr pipettes.

User Loso
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1 Answer

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Final answer:

Blow-out pipettes are designed to deliver their entire content and are distinguished by frosted bands, whereas Mohr pipettes have multiple graduations for variable volumes. In titrations, burettes are the tool of choice for their precision and control, not Mohr pipettes.

Step-by-step explanation:

The difference between blow-out pipettes and Mohr pipettes. To answer the question, option B) is the most accurate: Blow-out pipettes are designed to be emptied completely after liquid transfer, often indicated by a frosted band or two rings near the top, whereas Mohr pipettes, also known as graduated pipettes, have multiple graduation marks and are designed to deliver variable volumes up to the last graduation mark, not including the tip volume. Blow-out pipettes are generally used for volumes where the last drop matters and must be expelled by 'blowing out'. Mohr pipettes are typically used when such precision in delivering the last drop is not necessary. In terms of their use in titrations, burettes rather than Mohr pipettes are the preferred tool because they can accurately indicate the volume of liquid dispensed to a high degree of precision and are equipped with a valve to control the delivery, features that Mohr pipettes do not possess.

User Vrasidas
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