The law of Shari'ah regarding inheritance, wasiyyats (bequests) and Islamic wills

Q:

1. What are the guidelines of Shari'ah one needs to keep in mind when distributing the inheritance of the deceased and is it compulsory for one to prepare an Islamic will in his lifetime?

2. If one did not prepare an Islamic will, then how will his inheritance be distributed among his heirs after his demise?

3. What should be included in the Islamic will?

4. Is it permissible for a person to bequeath wealth for an heir or a non-heir upon his demise?

5. How will the estate be distributed in the case where one has debts and one has also made a bequest for certain people? 

6. What types of bequests are permissible and impermissible in Shari’ah?

Making wudhu with nail polish

Q: Why is wudhu not valid if someone wears nail polish? Wudhu is a matter of cleanliness, so if anyone wears it after cleaning their nails then the dirt will only touch the nail polish. When performing wudhu, the nail polish will be washed. So why should the water should reach the nail? 

Husband using a portion of wife's salary

Q: I am a Muslim woman who is working and married. My parents have a low financial condition for which I support them even after marriage. I give 30% of my salary to my parents and 70% to my husband. But my husband is now restricting me from giving money to my parents even after knowing their financial condition. What should I do?

My husband wants me to invest my salary in some good schemes so that it will be beneficial for me and my husband in the future. Whom should I listen to because not giving money to my parents will cause them great difficulty in surviving. Would using that money in increasing my wealth be a sin or not?

When should the tasmee and tahmeed be recited?

Q: 

1. I am a student of deen. I wish to know whether the imaam and muqtadee should recite tahmeed in salaah? If they should recite it, then when should they recite it? Should they recite it while rising from ruku or while standing in qaumah? I have heard that there is a difference of opinion in the Hanafi Mazhab in regard to this mas’alah.

2. Should the munfarid recite tasmee and tahmeed or only tahmeed?