Asselamu Aleikum I heard that a pure water, over which hand is immersed in couldn't be used for wudhu. Is that right?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

If a person puts his pure hand in pure water while he is not intending to perform ablution or Ghusl (ritual bath), then the water remains pure and one can perform ablution or Ghusl with it.

 Ibn Taymiyyah said: “It is confirmed that the Prophet put his water in a container in order to take a handful of it after he had washed his face. It is also confirmed that he also put his hands in water to take a handful of water while he was in a state of sexual defilement and he did not overburden the Muslims in this situation. We know for sure that the Muslims mostly performed ablution and Ghusl from small containers in his time and that they used to put their hands when performing ablution and Ghusl and whoever considers this water as being used [i.e. not acceptable to perform ablution and Ghusl with it], then he has restricted what Allaah permitted.”