Query Help With 2 Tables Plus One More - Easy I Think

I have two tables (tblRequest and tblDev) whose items have many-to-many
relationships with each other. I have set things up like this
(simplified):

Table 1 fields: tblRequest.PrimaryKey tblRequest.Description
example: 10 45 Elm
11 63 Green
12 123 Main Street
13 23 Pine

Table 2 fields: tblDev.PrimaryKey tblDev.Description
example: 20 Local. No issues
21 City owned and main
22 Out of county
23 Not seen by officer

Then Table 3 keeps track of the relationships between tables 1 and 2 by
tracking the primary key of the linked items in tables 1 and 2.
Table 3 fields: tblLink.RequestPrimaryKey tblLink.DevPrimaryKey
10 20
10 21
11 22
12 22

Items from tables 1 and 2 may or may not have a relationship listed in
table 3.

So given an item in tblRequest:
tblRequest.PrimaryKey tblRequest.Description
12 123 Main Street

I need two queries...
The first query would return ALL items from tblDev that are not
associated with this item in tblRequest - in this case 20, 21, 23.

The second query would return ALL items from tblDev that ARE associated
with this item in tblRequest - in this case 22.

That's it. Thanks in advance