What is the ruling on writing Quranic verses with a whiteboard marker that contains alcohol, assuming the impurity of Khamr (wine/alcohol), and is one sinful for sitting in a hall where Quranic verses are taught when written with this pen?

Scholars have differed regarding the impurity of alcohol. If an impure or forbidden substance transforms into another permissible substance (Istihalah - transformation), or if it mixes with another pure substance such that its impure and forbidden characteristics disappear (Istihlak - consumption/dissolution), then it becomes permissible.

Based on this, additives containing consumed or transformed alcohol, such as colorants and emulsifiers, are considered permissible (halal).

However, if Istihalah does not occur, or if the alcohol is not consumed (i.e., its smell remains), then it is not permissible to write the Qur'an with it, according to the view that it is impure. In fact, it is forbidden to write it with anything impure, and the writing must be washed off or burned if written with it.

Some scholars have issued a fatwa stating that alcohol is not impure and is not considered Khamr (wine), and this is the view adopted by some accredited fatwa-issuing bodies. According to this view, there is no harm in using alcohol for writing or other purposes.

There is no harm in attending a lecture where the Qur'an is written with pens containing alcohol, as long as you do not use these pens yourself to write the Holy Qur'an.