Answer:
The volume would become 2.34 L if the temperature dropped to 11.0 °C
Explanation:
From the question, A balloon was filled to a volume of 2.50 L when the temperature was 30.0 °C.
To determine what the volume will become if the temperature dropped to 11.0 °C, we will use one of the Gas laws that relates Volume and Temperature. The Gas law that relates Volume and Temperature is the Charlse' law which states that, "the Volume of a fixed mass of gas is directly proportional to its Temperature ( in Kelvin) provided that the Pressure remains constant"
That is
V ∝ T ( at constant pressure)
Where V is the Volume
and T is the Temperature in Kelvin
Then, we can write that
V = kT
Where k is the constant of proportionality
Then,

Hence, we can write that

∴ 
Where
is the initial volume
is the initial temperature
is the final volume
and
is the final temperature
From the question,
= 2.50 L
= 30.0 °C = 30.0 + 273.15 K = 303.15 K
= ??
= 11.0 °C = 11.0 + 273.15 K = 284.15 K
Putting the values into the equation, we get

∴ 

Hence, the volume would become 2.34 L if the temperature dropped to 11.0 °C.