The diary is never referred to as a horcrux until book 6 - not everyone taking the quiz will know what you're talking about with that question. Also, it should be phrased in a way that doesn't have multiple ways of answering it, like "With what implement does Harry destroy the diary?" Asking "how" he destroys it could involve a million different variations of "he stabbed it with the fang of a basilisk," none of which would be accepted. Also, please be consistent with Ginny - if her first name alone is acceptable for the first question, it should also be acceptable for the second. Finally, for "How does Harry find out?", you should accept "Riddle's diary", "Tom's diary", and "Tom Riddle's diary"... basically any answer that ends in "diary".
Can you accept "womping willow". also for tom riddle could you accept "voldemort". For basilisk fang you could accept just "fang" or maybe "tooth". This was a good quiz and I enjoyed it, I just missed a few answers because they weren't accepted. :)
It wouldn't make sense to spell it 'womping' because no one spells it like that. If you want to get the answer, just spell it correctly. Voldemort is not what he was known as at that time. So why would you call him Voldemort. And it isn't just a fang or a tooth, it is specifically a 'Basilisk Fang' in my opinion 'fang' or 'tooth' is too general to count.
When you ask 'who saves Harry's life?' I think you should put 'Who saves Harry's life when he is in the chamber?' This would help as I was trying to spell out Dobby as her saves his life at the end with Lucius!
The Malfoy family owned Dobby, not just Lucius Malfoy. I think maybe basilisk venom should be accepted because that was what really destroyed the horcrux. I didn't miss any though (except for one I couldn't remember the answer to) anyway and it was a good quiz.