What is the ruling on shaving one`s beard?

All Perefct Praise is due to Allah The Lord of The Worlds.

Growing a beard is mandatory and must be abided by except for a sound reason. And Allah Knows Best.

What should a woman who is in a state of menstruation, or confinement do if she became ritually pure during the day of Ramadhaan ?

If she became pure during the day time of Ramadhaan, it is desirable for her to fast the rest of that day, and to make up for it along with the days that she had missed due to menstruation.

Is Zakah(obligatory charity)due on an indebted merchant?

Debt doesn`t abrogate the dueness of Zakah, thus a debtor who has money, articles of merchandise, or other Zakah funds at his disposal should pay Zakah from them.

Is Zakah(obligatory charity) due on articles of merchandise even if they were stacked in the merchant`s stores for years?

Yes, Zakah is due on stored articles of merchandise even if they were stacked in the merchant`s stores for years because this is the way Islam has countered monopoly.