What is the ruling on wiping the white area behind the ears instead of wiping the head?
The obligation in ablution is to wipe some of the head; it is not a condition to wipe all of it. Wiping the white area behind the ears suffices for that. And Allah the almighty knows best.
What is the ruling on Friday Ghusl (ritual bath)?
Friday Ghusl is a confirmed Sunna (Prophetic tradition) even if a person wasn`t in a state of Janbah (ritual impurity), or physically unclean. However, one who doesn`t make Ghusl on Friday isn`t sinful for the Prophet (PBUH) said: "It is good for a Muslim to make ablution for Friday prayer, but it is better to make Ghusul. [At-Tirmithi & Abu Dawood].
How is night prayer offered?
Night prayer is offering voluntary prayer after Maghrib and before Fajr (Dawn). As for Tahajjud, it is offering voluntary prayer at night after waking up voluntarily, and for Allah`s sake as He Says (What means): "And pray in the small watches of the morning: (it would be) an additional prayer (or spiritual profit) for thee: soon will thy Lord raise thee to a Station of Praise and Glory!" [Al-Isra`/79]. Offering Tahajjud is better than offering voluntary prayer before going to bed.
I`m keeping a plot of land (10 Dunums) for my children. Is it liable for Zakah?
Praise be to Allah, The Lord of the Worlds.
Land that is purchased with the intention of ownership and personal benefit—meaning to retain it for use and not for trade—is not subject to zakāh, as such property is not considered from trade commodities (ʿurūḍ al-tijārah).
It is stated in Al-Ḥāwī al-Kabīr:
“If it is property and one intends it for trade, then zakāh is due upon it; but if he intends it for personal possession, then no zakāh is due upon it.” And Allah, the Exalted, knows best.