Are the walls and floor of a house considered impure if they are painted with a paint that contains alcohol, and is it permissible to pray in it?

It is clear that you are afflicted with waswasa (whispers/obsessive thoughts), and we warn you against indulging in them. The issue of alcohol's impurity is a matter of differing opinions, and you may adopt the view of those who consider it pure. Even if it is considered impure, you are only required to remove the impurity from the ground for the purpose of prayer on it. You can also place a prayer rug over the impure spot to pray on it.