Tom should use a ladder that is smaller or at the the same height of the window frame. Here it says that he is using a ladder that is taller than the window frame, and this can be very uncomfortable for the person who is using the ladder, so it would be recommendable for Tom to use a smaller ladder, probably a ladder that is only a few inches smaller or taller than the window frame. Using a ladder that is like this should be safe to use.
Sodium oxide is a simple strongly basic oxide. It is basic because it contains the oxide ion, O2-, which is a very strong base with a high tendency to combine with hydrogen ions. Reaction with water: Sodium oxide reacts exothermically with cold water to produce sodium hydroxide solution
