Is it permissible to offer prayer at home, or should it be offered in the mosque?
All perfect praise be to Allah, The Lord of The Worlds. It isn`t preferable for the man to pray at home as praying in the mosque is twenty seven times more rewarding. Therefore, this should motivate him to offer prayers in the mosque. And Allah Knows Best.
Does the clipping of nails nullify ablution?
No, it does not, and it is preferable to wash the hands afterwards.
What is the ruling on training dogs that are of benefit?
All perfect praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
This is permissible because Allah The Almighty Says (What means): "They ask thee what is lawful to them (as food). Say: lawful unto you are (all) things good and pure: and what ye have taught your trained hunting animals (to catch) in the manner directed to you by Allah. eat what they catch for you, but pronounce the name of Allah over it: and fear Allah. for Allah is swift in taking account." [Al-Ma`idah/4]. However, it is prohibited to keep dogs for no benefit because Salim reported on the authority of his father that Allah's Apostle (PBUH) said: "He who kept a dog other than one meant for hunting or for watching the herd, lost two qirat of his reward every day." [Moslim]. And Allah The Almighty Knows Best.
What is the ruling of Sharia on Zina and what is the punishment for the unmarried man who commits this grave sin?
Praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
The punishment for Zina (Adultery and extramarital relations) is the same for men and women: 100 lashes for the unmarried to be witnessed by a group of the believers. Definitely, this person has incurred the wrath of Allah; however, he must make repentance immediately, refrain from this grave sin, and seek Allah`s forgiveness. And Allah The Almighty Knows Best.