What is the expiation for perjury?
Perjury is forbidden and one of the major sins that require turning to Allah in repentance, seeking His forgiveness, giving back rights to whom they belong, or seeking their forgiveness, and expiating for that oath.
Is it permissible for a person who had vowed to give a certain amount of money to another, but didn`t find the latter to donate that money to the mosque?
In principle, the vowing person should abide by his vow as much as possible. Therefore, if he couldn`t find the person that he had made the vow for, then the vow itself is countless and nothing is due on its maker. However, if the latter happens to find the former later on then, he has to give him that money.
Is committing Zina (Adultery and extramarital sex) without the intention of getting pregnant or deflowered considered full Zina?
All perfect praise be to Allah the Lord of the Worlds. May Allah`s peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
The Messenger of Allah (PBUH) says: "The eyes commit fornication, the hands, the feet, and the private parts." [Musnad Ahmad, P.3912]. Sheikh Shu`aib `Arn`oot graded this Hadith as sound. What you are asking about is far graver. Generally speaking, sincere repentance erases sins, good deeds erase bad deeds, and fearing Allah stops one from committing this heinous act. In addition, the devil is man`s worst enemy and whoever surrenders themselves to the wolf will be eaten. And Allah The Almighty Knows Best.
I prayed all the obligatory prayers in congregation, but after finishing the `Isha prayer, I remembered that I had forgotten to pray Dhuhr. What should I do, and is my prayer invalid?
Your prayers are valid, but you must make up the Dhuhr prayer as soon as you remember it, based on the saying of the Prophet (peace be upon him): "Whoever forgets a prayer must pray it as soon as they remember it; there is no expiation for it except this." [Muslim]. And Allah knows best