We can only see things if they give off light but be we use other senses to gather information about things we cannot see.
Covalent bonds and it is between the hydrogens (hydrogen bonds)
<span>Nitric acid is often manufactured from the atmospheric gases nitrogen and oxygen, plus hydrogen prepared by reforming of natural gas, in a two-step process. In the first step, nitrogen and hydrogen react to form ammonia:
In the second step, ammonia and oxygen react to form nitric acid and water:</span>
According to Raoult's law, Vapor pressure is directly proportional to the mole fraction of the solution. As 1.0 M CaF2 has least moles here, it has lowest vapor pressure.
In short, Your Answer would be Option D
Hope this helps!
