Answer:
The answer to your question is It will be formed 0.39 moles of H₂
Explanation:
Data
moles of H₂ = ?
moles of HCl = 0.78
moles of Zinc = excess
Balanced chemical reaction
2 HCl + Zn ⇒ 1 H₂ + ZnCl₂
Process
1.- Use proportions to solve this problem. Consider the coefficients of the balanced reaction.
2 moles of HCl ---------------------- 1 mol of H₂
0.78 moles of HCl ----------------- x
x = (0.78 x 1) / 2
- Simplification
x = 0.78 / 2
- Result
x = 0.39 moles of H₂
Given information : Sample of 
We need to find the moles of Chlorine in the given sample.
We can say that we need to find moles from the given atoms.
Relation between mole and atom is given by : 
Where
is Avogadro number.


On solving the above equation , atoms(unit) gets cancelled out and we get 0.0286 mol.
In the given sample the moles of Chlorine (Cl) is 0.0286 mol , so option A is correct.
Answer:
N2O5
Explanation:
IUPAC ID: Dinitrogen pentoxide
Molar mass: 108.01 g/mol
Density: 1.64 g/cm³