ANS:C - 120

The vacuum maintained in a vacuum distillation unit for reduced crude is typically around 1.2 mmHg (millimeters of mercury). Here’s why:

1. Vacuum Distillation: Vacuum distillation is a process used to separate components of crude oil or other feedstocks that have high boiling points. It operates under reduced pressure (vacuum) to lower the boiling points of the components and avoid thermal degradation.
2. Vacuum Level: The specific vacuum level maintained in the vacuum distillation unit depends on several factors including the properties of the feedstock (such as reduced crude), the desired separation efficiency, and the design of the distillation equipment.
3. Typical Vacuum: In the case of vacuum distillation for reduced crude oil, the vacuum is typically maintained around 1.2 mmHg. This low pressure helps to lower the boiling points of heavy fractions, such as vacuum gas oil, while minimizing thermal cracking and improving product quality.