Questions

Ammonia is a base. One adding ammonia to water,the resulting solution will become basic. pH of an alkaline solution is 7. So the pH will increase

Therefore the answer for What travels around the world but stays in one spot is STAMP or any other thing that acts as a stamp does.

Ex. the letter in the envelope etc...

Since, Several things have the possibility, but the word travel evokes that it would move. 

The combined gas law states that the ratio between the pressure-volume product and the temperature of a system remains constant.

Hence it depends on all the three Volume, Temperature & Pressure.

The amount of money you’ll get for a given amount of your country’s currency is based on internationally determined exchange rates. Exchange rates can be either fixed or floating. Fixed exchange rates use a standard, such as gold or another precious metal, and each unit of currency corresponds to a fixed quantity of that standard that should (theoretically) exist.

It is a protocol used to advertise the set of networks that can be reached with in an autonomous system. BGP enables this information to be shared with the autonomous system. 

The alphabet 'Y' resembles same as the questioning word WHY in sounding.

Hence,  alphabet Y is a question.