Answer:
In 1827, Brown observed, using a microscope, that small particles ejected from pollen grains suspended in water executed a kind of continuous and jittery movement, this was named “Brownian motion”. ... This random movement of particles suspended in a fluid is now called after him.
Explanation:
HOPE this helps :)
If you would draw the Lewis structures of these atoms, you would see that A has 2 electron pairs and 2 lone electrons (that can bond). For B you’d see that you only have 1 electron that can form a bond. This means that 1 atom of A (2 lone electrons) can bond with 2 atoms of B. To know the kind of bond you have to know wether or not there will be a ‘donation’ of an electron from one atom to another. This happens when the number of electrons on one atoms is equal to the number of electrons another atom needs to reach the noble gas structure. As you can see, this is not the case here. This means that you get an AB2 structure with covalent character.
Answer : The unit of 
in mol/L.mm Hg is, 
Explanation :
As we know that the is the Henry's Law constant for argon at 
is, 
Now we have to determine the unit of in mol/L.mm Hg
Conversion used for pressure from atm to mmHg is:
1 atm = 760 mmHg
So,
Thus, the unit of in mol/L.mm Hg is,
It is lead (ll) iodide or just lead iodide
