Explanation:
its answer is displacement reaction
The number of moles of H₂ that are needed to react with 2.0 moles of N₂ is 6.0 moles
<u><em>calculation</em></u>
N₂ +3H₂→ 2NH₃
The moles of H₂ is calculated using the mole ratio
That is from equation above N₂:H₂ is 1 :3
therefore the moles of H₂ = 2.0 moles x (3/1) = 6.0 moles
To know the number of atoms, it will be necessary to use the formula of avogadro. We calculate the number of moles then we can calculate the number of avogadro.
The molar mass of:
Phosphorus = 31g / mol
Mercury = 200 g / mol
Bismuth = 209 g / mol
Strontium = 87 g / mol.
The number of avogadro (N) is 6.023 10 ^ 23
n = m (mass) / M (molar mass)
number of atoms = n. N = m / M . N
number of phosphorus atoms = 5.14/31 . 6.023 10^23 = 9.98 10 ^ 22 atoms
Number of atoms of mercury = 2.16/200 . 6.023 10^23 = 6.5 10 ^ 21 atoms
Number of bismuth atoms = 1.8/209 . 6.023 10^23 = 5.18 10 ^ 21 atoms
Number of strontium atoms = 8.8 x 10-2 /87 . 6.023 10^23 = 6.09 10 ^ 20 atoms
Answer: The correct option is Aluminium.
Explanation: To recover copper from the solution, we require a metal which can easily displace copper from the solution.
The reactions in which metal displaces another metal in a chemical reaction are known as single displacement reactions. These reactions are studied using reactivity series.

A is more reactive than B.
The metal which lie above in the reactivity series will easily displace the metal which lies below in the reactivity series.
From the given options, Aluminium is the most reactive of all the metals and hence, it is the best choice for recovering copper from its solution.