excessive velocity
The faucet is clogged
A clogged aerator on the end of the faucet would cause the water flow to decrease in that faucet.
Nothing, it can not do that .
The rubber stop washer has failed.
check for leaks
Someone may have shut off the water to that faucet, or a pipe may have froze, or there may be air in the pipe.
No, if the current faucet doesn't have a sprayer, there is no place on the faucet to attach the sprayer. It would attach on the underneath side of the faucet in the center.
No conversion, it would need to be replaced with a single handle faucet.
Faucet side.
It all depends what faucet is running if it is a kitchen or lavatory faucet it would be roughly 3 gallons if it was a tub and shower faucet it would roughly 15 gallons
If you have bubbles coming out of your kitchen faucet, you have a venting problem. It has nothing to do with soap in your faucet.
If water gets under a faucet washer it can cause a loud vibration when the water is turned on. You either need to find a proper replacment or get a new faucet.