The molarity of a solution equals to the mole number of the solute/the volume of the solution. For NH4Br, we know that the mole mass is 98. So the molarity is (14/98) mol /0.15 L=0.95 mol/L.
Hydrogen Bonding occurs when the hydrogen atom of one molecule is bonded with a molecule of high electronegativity element like nitrogen of another molecule.
It is a type of dipole-dipole interations.
The nitrogen is a highly electronegative element that forms a weakbond with the hydrogen atom of another molecule with dipole-dipoleinteraction.
Hydrogen bonds are weaker than covalent and ionic bonds.