Breaking a nafil Salaah
Q: A person is performing two rakaats of a Nafl Salaah, either Tahujjud, Chaast, or Ishraaq. During this salaah, his wudu breaks. By the time wudu is made and he returns to repeat this broken Nafl salaah, the time for that Salaah expires.
1. Is Qaza necessary?
2. If so, should it be performed at any particilar time?