My husband works for a major phone retailer - definitely don't immerse your mobile phone in water - with or without the battery as the phone's other components are not waterproof and it will usually void your warranty!
There are a number of things that could happen when you break open a worn out cell phone battery. You could have battery acid leak on your hands for example.
yes it can
If you get the phone wet, put it in a bag of rice. The rice will help draw the water away from the battery.
take the battery out and put both the phone and battery in a container of rice, it helps dry everything out
yes it does
It would break.
Anything electrical can break ! A phone could be dropped in water (which may 'short-out' the circuitry). You could damage the power socket - making it impossible to recharge the phone.
drop it in some water or go out and throw it at the sidewalk
Turn off your phone, take off the back and take out the battery. look in the area where the battery sits for a small square sticker. if its white there is no water damage, if the sticker is pink or red the phone has suffered water damage.
first make it dry in the sunlight fully. and try to use in the cell phone. it works in my nokia phone when i put it into the water.
With or without the battery the water that is in the alcohol can damage the circuitry and components.
To see if your phone can be repaired after dropping it in water all depends on the circuit board of the phone. A way to check this is to remove the battery and look for a white or red dot behind where the battery was, if it is white you can get it fixed, if it is red then the phone is most likely done.