Certain du'a in the Quran are meant for oneself, but sometimes for more than two persons. But sometimes when we make du'a for our own self, we should use the singular form instead of the plural form and if we make du'a in a group, we should use plural form instead of singular form.

For example:

1. Rabbana zhalamna anfusana (plural)... to Rabbi zhalamtu nafsi.. (singular)?
2. Rabbighfirli wa liwalidayya warhamhuma kama rabbayani shaghira (singular) to Rabbighfirlana wa liwalidina warhamhum kama rabbauna sighara (plural)?


Does anyone has the whole (and grammatically correct) compilation of these du'a (in singular/plural forms)?