Answer : The percent composition of Pb and Sn in atom is, 3.21 % and 96.8 % respectively.
Explanation :
First we have to calculate the number of atoms in 5.5 wt% Pb and 94.5 wt% of Sn.
As, 207.2 g of lead contains
atoms
So, 5.5 g of lead contains
atoms
and,
As, 118.71 g of lead contains
atoms
So, 94.5 g of lead contains
atoms
Now we have to calculate the percent composition of Pb and Sn in atom.


and,


Thus, the percent composition of Pb and Sn in atom is, 3.21 % and 96.8 % respectively.
Explanation:
that u know right .........................
I'm not sure if this is what you're looking for, but I suppose you would have to have the solute and the solution to balance the reaction.
Answer: The statement conjugate base of hydrofluoric acid is weaker than that of acetic acid is most likely true.
Explanation:
A strong acid upon dissociation gives a weak conjugate base. This can also be said as stronger is the acid, weaker will be its conjugate base or vice-versa.
Hydrofluoric acid is a strong base as it dissociates completely when dissolved in water.
For example, 
The conjugate base is
which is a weak base.
Acetic acid is a weak acid as it dissociates partially when dissolved in water. So, the conjugate base of acetic acid is a strong base.

Thus, we can conclude that the statement conjugate base of hydrofluoric acid is weaker than that of acetic acid is most likely true.