Question

Ammonia is filled in weather balloons that work at very high altitudes because it is:
A. A neutral gas
B. A compound of nitrogen
C. Lighter than air
D. Liquefied at low temperature

Answer 1

Hint - In order to deal with this question first we will describe weather balloons, how they are made and what are its uses and special features further we will proceed by finding the reason why ammonia is filled in weather balloons and its advantages over other gases.

Complete step-by-step answer:
Weather balloon also known as sounding balloon is a balloon (specifically a type of high-altitude balloon) that carries instruments aloft to send back information on atmospheric pressure, temperature, humidity and wind speed by means of a small, expendable measuring device called a radiosonde.
To obtain wind data, they can be tracked by radar, radio direction finding, or navigation systems (such as the satellite-based Global Positioning System, GPS).
A lifting gas or lighter than air gas is a gas that has a lower density than normal atmospheric gases and rises above them as a result. It is required for aerostats to create buoyancy, particularly in lighter-than-air aircraft, which include free balloons, moored balloons, and airships. Only certain lighter than air gases are suitable as lifting gases.
Ammonia is sometimes used to fill weather balloons. Due to its high boiling point (compared to helium and hydrogen), ammonia could potentially be refrigerated and liquefied aboard an airship to reduce lift and add ballast (and returned to a gas to add lift and reduce ballast).
Hence, Ammonia is filled in weather balloons that work at very high altitudes because it is lighter than air.
So, the correct answer is option C.

Note- Balloons meant to stay at a constant altitude for long periods of time are known as transondes. Weather balloons that do not carry an instrument pack are used to determine upper-level winds and the height of cloud layers. For such balloons, a theodolite or total station is used to track the balloon's azimuth and elevation, which are then converted to estimated wind speed and direction and/or cloud height, as applicable.