Is it permissible for a woman to wear underwear while performing Umrah?
Yes, it is permissible for a woman to wear underwear while performing Umrah. This is because she should keep her regular clothes that cover all her body while being in a state of Ihram (ritual consecration) for Hajj, or Umrah. However, she should uncover her face and hands, but it is permissible for her to let her head-covering garment drape from her head down over her face when non-Mahram (i.e., marriageable) men pass by her. And Allah Knows Best.
Is Zakah (obligatory charity) due on the items used in the trading process such as: cars , shops etc..?
No Zakah is due on equipments used in the trading process such as cars and the like.
What is the ruling on selling sacrificial animals (udhiyah) described with specific attributes and authorizing an agent to slaughter them?
Praise be to Allah, and peace and blessings be upon our Master, the Messenger of Allah.
Selling sacrificial animals (udhiyah) that are described with specific attributes is permissible. This falls under the category of a salam sale (forward sale) if conducted using the terminology of salam, and under the category of a regular sale if not using the terminology of salam.
As for authorizing the seller to slaughter the sacrificial animal, the basic principle is that it is permissible, because the agent (wakil) stands in the place of the principal (muwakkil) in achieving his objective. This is a contract that the principal (the buyer) is entitled to perform himself, so authorizing another (the seller) to do so on his behalf is valid.
However, it is a condition for authorization to slaughter that the intention (niyyah) is present either at the time of slaughter or at the time of handing over the sacrificial animal to the agent. The basic principle is that the sacrificial animal must be specifically designated, as it is an act of worship. It is not required to designate it at the time of slaughter; rather, it is valid to do so before that.
It is permissible for the principal either to delegate the intention to the agent or to formulate it himself when authorizing the agent to slaughter. However, the sacrificial animal must be designated, even if at the time of slaughter, by the agent.
It is obligatory to designate the sacrificial animals so that each person offering a sacrifice receives his own specific animal. Therefore, charitable organizations and companies must take this into consideration and establish a specific mechanism that ensures no mixing of sacrificial animals occurs, so that each person offering a sacrifice receives his own designated animal. And Allah Almighty knows best.
When does the time for Udhiyah begin?
Praise be to Allah, and peace and blessings be upon our master, the Messenger of Allah.
The time for Udhiyah (sacrificial offering) begins once the sun has risen on the day of Eid al-Adha—which is the tenth of Dhul-Hijjah—and a period of time has passed equivalent to two brief prayer units (Raka'at) and two brief sermons (Khutbah). It then continues until the sunset of the last of the days of Tashreeq, which are the eleventh, twelfth, and thirteenth of Dhul-Hijjah.
The Prophet (peace be upon him) said: "All the mountain passes of Mina are places of sacrifice, and in all the days of Tashreeq there is slaughtering." [Narrated by Al-Bayhaqi and Ibn Hibban].
The best time to slaughter is after finishing the Eid prayer, due to the saying of the Prophet (peace be upon him):
"Indeed, the first thing we begin with on this day of ours is to pray, then we return and slaughter. Whoever does that has attained our Sunnah, and whoever slaughters before [the prayer], it is only meat he has presented to his family; it is not part of the ritual sacrifice (Nusuk) in any way." [ٌReported by Bukhari & Muslim].
It is valid to sacrifice at any time, whether by night or by day; however, it is disliked (Makruh) at night. And Allah the Almighty knows best.