Answer:
Explanation:
Sure you can - Mercury and water are both liquid at room temperature and atmospheric pressure. But Mercury is much much heavier or denser than water. So much that the two substances will not mix. The lighter water can be separated by pouring it out while the heavy Mercury will stay in the bottom.
Where's the list? It depends on which one it is. It could be Chlorine, silicon, or anything on the non metals side of the periodic table if you don't list it.
There is a shortcut trick while doing such fill in the blanks of nuclear reactions of hydrogen and helium
Let a,b,care elements of set N

Now
for our question
Hence b=4-3+1=1+1=2
So
The missing place should b e deuterium of heavy water
In nuclear reactions energy is released so it's mentioned on product side not reactant side
When 2 different kinds of matter make contact, if they react to each other, they simply exchange atoms, not making any new matter in the process, they simply gets turned into something different.