I don't know about the HCI, but it has water, and a little salt, among other compounds. It is close enough to the formula of tears, that if you use a clean finger and wet it with saliva, you can wipe a foreign object out of your eye, without pain. That is, if there are no drops, or anything else, and your eye is irritated by something in it.
No, saliva doesn't contain any Hcl, at least not in any significant amount. Its composed of water, mucus and only ONE enzyme, which is amylase, a protease (protein enzyme). Only proteins begin chemical digestion in saliva.
Saliva is made up of atibacterial compounds, mucus, various types of enzymes HOWEVER around 97-98% is actually just water and along with this water it carries electrolytes.
Saliva contains no HCI, and is manly made up of water. Saliva comes from your saliva glands at the back of your mouth, and it is used to help taste food, and stop your mouth getting dry