1. False; all outputs are fixed length, so there's a unique hash value for a null input.
2. Avalanche.
3. The LM hash password is actually two 7-character halves concatenated; the LM hash password is not case-sensitive.
4. The server challenge is randomly generated and used to encrypt the response, so every challenge would result in a different network hash for the same password.
5. NetBIOS Name Service.
6. False; the opposite is true.
7. mask==?d?d?s[Q-Zq-z][Q-Zq-z]
8. False; the tool is called John the Ripper.