a
B-flat to C-sharp is an augmented 2nd.
Major third
Yes
Major first. (+1)
A C to a G would be a perfect fifth. Because the interval was decreased by 2 half-steps (by sharping the C and flatting the G), the interval C sharp to G flat is a double-diminished 5th.
E flat consists of 3 flats, B flat, E flat and A flat. E flat to B flat would be a perfect 5th interval as B flat is in E flat major, but because your question was E flat to B, B is a semitone up from B flat, this would mean the interval becomes a semitone larger, and a semitone larger from a perfect interval is augmented. Therefore, the answer to your question is an augmented 5th. Hope this helps :)
The interval from F sharp to D sharp is a major sixth. In terms of scale degrees, F sharp to D sharp spans nine half steps. This interval can also be described as the distance between the first and sixth notes of the F sharp major scale.
C sharp/D flat, D sharp/E flat, F sharp/G flat, G sharp/A flat, A sharp/B flat
the interval is a 3rd.
a flat( or g sharp),a, b flat( or a sharp), b, c flat (or b sharp), c, c sharp (or d flat), d, e flat (or d sharp), e, f flat( or e sharp), f, f sharp ( or g flat)and g.
a flat( or g sharp),a, b flat( or a sharp), b, c flat (or b sharp), c, c sharp (or d flat), d, e flat (or d sharp), e, f flat( or e sharp), f, f sharp ( or g flat)and g.
No. There are a (plus a flat and a sharp), b (plus b flat and b sharp), c (flat and sharp), d (flat and sharp), e (flat and sharp), f (flat and sharp), and g (flat and sharp). That makes a, b, c, d, e, f, g Plus the flat and sharp for each, making 21 notes of the scale.