Clock no longer sounds alarm

That is frustrating. My guess is not in any way technical issue, but i will advice you to check some stuff in your ipad settings.

First start by going Settings > General > Date & Time and confirm that you have the right Time Zone and Date set correctly. Second try checking your Sound options. If nothing seems to fix your issue, just restore it to factory settings and try again setting an alarm. Dont forget to keep backup of your things before restoring it.