PbO2
You have to take the mass of lead in the problem, and divide by the molar mass.
When you do the same with oxygen, you get a number about twice as large as when you divide the mass of lead by the molar mass of lead. This means that the simplest formula would be PbO2
Answer : The normality of the solution is, 30.006 N
Explanation :
Normality : It is defined as the number of gram equivalent of solute present in one liter of the solution.
Mathematical expression of normality is:

or,

First we have to calculate the equivalent weight of solute.
Molar mass of solute
= 94.97 g/mole

Now we have to calculate the normality of solution.

Therefore, the normality of the solution is, 30.006 N
The molarity is the number of moles in 1 L of the solution.
The mass of NH₃ given - 2.35 g
Molar mass of NH₃ - 17 g/mol
The number of NH₃ moles in 2.35 g - 2.35 g / 17 g/mol = 0.138 mol
The number of moles in 0.05 L solution - 0.138 mol
Therefore number of moles in 1 L - 0.138 mol / 0.05 L x 1L = 2.76 mol
Therefore molarity of NH₃ - 2.76 M
Explanation:
Vapor pressure is defined as the pressure exerted by vapors or gas on the surface of a liquid.
Vapor pressure is inversely proportional to the number of solute particles. Hence, more will be the solute particles lower will be the vapor pressure and vice-versa.
(a) 
It dissociates to give two particles.
(b) 
Total number of particles it give upon dissociation are 1 + 2 = 3. Hence, it gives 3 particles.
(c) 
Total number of particles it give upon dissociation are 1 + 3 = 4. Hence, it gives 4 particles.
(d) Surcose being a cobvalent compound doe not dissociate into ions. Therefore, there will be only 1 particle is present.
(e) 
Total number of particles it give upon dissociation are 1 + 1 = 2. Hence, it gives 2 particles.