The subscript 2 indicate that there are two atoms of chlorine in the compound.
<u><em> Explanation</em></u>
Subscript in the chemical formula indicate the number of atoms of the element immediately before the subscript.
In MgCl₂ there are two(2) atoms of chlorine since Subscript 2 is immediately after chlorine.
Hydrogen bonding is an attractive force between a hydrogen atom attached to a electronegative element
Considering ideal gas behavior, the volume of 1 mol of gas at STP is 22.4 L; then the volume occupied by 1.9 moles is 1.9mol*22.4L/mol
The answer is 43 L if I am correct.
