Any help with solving the following clues would be appreciated.
All from a quiz and do not have any letters
1. Slavonic mark containing itself - hack takes the point (5 letters)
2. Dance movement by gliding and exchange (6-6 letters)
3. Internal murmur with light food (7 letters)
4. Starter as the prisoner makes a dash (7 letters)
5. Political demonstration affects even me about ten (9 letters)
6. Composer of vocal duet for Mr.Ritz and Mr. Spencer (5,6 letters)