The volume of a gas that its pressure increase to 3.4 atm is calculated as follows
By use of boyles law that is P1V1=P2V2
V1=4.0 L
P1=1.1 atm
P2=3.4 atm
V2= P1V1/P2
(1.1 atm x 4.0 L)/3.4 atm= 1.29 L
Reactivity of non-metals depend on their ability to gain electrons. So, smaller is the size of a non-metal more readily it will attract electrons because then nucleus will be more closer to valence shell. ... Hence, Br is the non-metal which will be more reactive than At.
