Step-by-step explanation:
We have to find the number of mEq in 4.5 L of 0.8 M solution of MgCl₂. First we can find the number of moles of MgCl₂ that are present in that solution.
The molarity can be calculate using the following formula.
molarity of a solution = number of moles of solute/(volume of solution in L)
We already know the concentration of the solution and the volume of solution in liters. So we can find the number of moles of the salt that are present in the solution.
molarity of a solution = moles of MgCl₂/(volume of solution in L)
moles of MgCl₂ = molarity of the solution * volume of solution in L
moles of MgCl₂ = 0.8 M * 4.5 L
moles of MgCl₂ = 3.6 mol
So we found that there are 3.6 mol of MgCl₂ in the solution. Now we have to find the number of Eq or mEq.
The equivalent mass of a salt can be defined like the molecular mass of the salt divided by the charge of the metal cation.
MgCl₂ ---> Mg²⁺ + 2 Cl⁻
The atom of Mg is transferring one electron to each atom of Cl. That means that it is losing two electrons.
Equivalent mass of MgCl₂ = molar mass of MgCl₂/2
That means that each mol of MgCl₂ contains two equivalents.
Equivalents of MgCl₂ = 2 * number of moles of MgCl₂
Equivalents of MgCl₂ = 2 * 3.6 Eq
Equivalents of MgCl₂ = 7.2 Eq = 7.2 Eq * 1000 mEq/Eq
Equivalents of MgCl₂ = 7200 mEq
Answer: There are 7200 mEq of MgCl₂ in the solution.