Can You Make Du`a in a State of Impurity?
Question

I would like to know whether a person who is in a state of post-sex impurity could make supplications and Dkikr (esp. Those recommended before going to bed).
Praise be to Allah.It is permissible for a person, if he is in a state of major impurity, to make Du`a to Allah and remember Him, including the Adhkar before sleeping and others. 
`Aishah (may Allah be pleased with her) said, “The Messenger of Allah (peace and blessings of Allah be upon him) used to remember Allah in all circumstances.” (Narrated by Muslim, Al-Hayd, 558)
Some of the commentators on this Hadith said: this Hadith is stating a basic principle, which is the remembrance of Allah in all circumstances, even when one is in a state of minor or major impurity. 
Dhikr in the form of Tasbih (saying `Subhan Allah’), Tahlil (saying `La ilaha ill-Allah’), Takbir (saying `Allahu Akbar’), Tahmid (saying `Al-hamdu Lillah’) and other similar Adhkar are permissible in all situations, according to the consensus of the Muslims. 
What is forbidden in a state of major impurity is Dhikr that consists of reciting the Quran , a full verse or more, whether that is read from the Mus-haf or recited by heart, because the prohibition of doing so has been narrated. 
But it is recommended for the person who is in a state of major impurity to wash his private parts and do Wudu when he wants to go to sleep, because of what is stated in the Hadith of `Umar (may Allah be pleased with him), who said, “O Messenger of Allah, may one of us sleep when he is in a state of major impurity? ” He said, “Yes, if he does Wudu.” (Narrated by Al-Bukhari, Al-Ghusl, 280) (See Ash-Sharh Al-Mumti` by Ibn `Uthaymin, 1/288; Tawdih Al-Ahkam by Al-Bassam, 1/250; Fatawa Islamiyyah, 1/232)
For more details, please see the following answers: 20847 , 27091 , 6533 , and 181351 . 
And Allah knows best.