Answer: Hydrogen that is not used in balloons because hydrogen burns very easily.
pls mark brainliest
Sorry this will probably be pretty long.
So think of the "control" as being something you yourself add to increase or decrease the effects in an experiment.
I'll give you an example so it is not as confusing.
Say you have decided to make an experiment on plants. Which plant can grow the fastest on which type of liquid? What is being added to this experiment? The liquid! Or all of the liquids you used. Like if you used Coke, Lime Gatorade, Orange Gatorade, and Water. Each drink will EFFECT each plant differently.
Hope I was of any hope?
Answer: Option (B) is the correct answer.
Explanation:
Expression for the given decomposition reaction is as follows.
Let us assume that x concentration of 
is present at the initial stage. Therefore, according to the ICE table,
Initial : x 0
Change : - 0.1 
Equilibrium : (x - 0.1) 0.2
Now, expression for 
of this reaction is as follows.
Putting the given values into the above formula as follows.
x = 0.12
This means that 
= x = 0.12 atm.
Thus, we can conclude that the initial pressure in the container prior to decomposition is 0.12 atm.
C. Lowering the temperature
At the lower temperature, particles have less kinetic energy, so they move slower.
is a Lewis acid due to the unfilled valence shell on carbon atom (possessing positive charge) it accepts electron readily.
is not a Lewis acid due to the presence of negative charge which represents that there are electrons available for donation.
is not a Lewis acid due to the presence of lone pair on nitrogen which is easily donated to the acceptors.
is a Lewis acid due to the availability of vacant p-orbital on boron atom.