Answer:
6. 15 oxygen atoms (The coefficient 5 is multiplied by the subscript 3 of oxygen)
7. The number "2" is the subscript.
Explanation:
A balanced equation is defined as the one that has equal number of atoms of all the elements present on both reactant and product side.
(a) 
Number of atoms on reactant side are as follows.
Mg = 1
O = 6
H = 3
Cl = 1
Number of atoms on product side are as follows.
Mg = 1
O = 9
H = 2
Cl = 2
So, to balance this equation we multiply
by 2 on reactant side and multiply
by 2 on product side.
Therefore, the balanced reaction equation is as follows.
(b) 
Number of atoms on reactant side are as follows.
S = 1
O = 4
H = 2
Number of atoms on product side are as follows.
S = 1
O = 4
H = 2
Therefore, this equation is balanced as it has same number of atoms on both reactant and product side.
(c) 
Number of atoms on reactant side are as follows.
Sr = 1
O = 1
H = 2
S = 1
O = 4
Number of atoms on product side are as follows.
Sr = 1
O = 1
H = 2
S = 1
O = 4
Therefore, this equation is balanced.
hydrogen bonding and ion-dipole
Explanation:
The intermolecular forces the particles of fluoride experiences is an ion-dipole bond, between the water molecules, there are hydrogen bonds.
- An ion-dipole bond is an attractive force between an ion and a polar molecule.
- The fluoride is the anion that is attracted by the positive end of water molecules.
- Water is a polar compound.
- Between the water molecule, there is presence of hydrogen bonds.
- Hydrogen bonds are special dipole - dipole attraction between polar molecules joined to a highly electronegative atom.
- The electrostatic attraction between the hydrogen atom of one molecule and the electronegative atom of a neighboring molecule forms the hydrogen bond.
learn more:
Hydrogen bond brainly.com/question/10602513
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