6 electrons... 's' can hold 2..... 'd' can hold 10 and 'f' can hold 14
4. Isotopes of the same element
Answer:
77.14 atm of pressure should be of an acetylene in the tank.
Explanation:

According to reaction, 2 moles of acetylene reacts with 5 moles of oxygen.
Moles of oxygen=
Moles of acetylene =

Volume of large tank with oxygen gas, 
Pressure of the oxygen gas inside the tank = 
..[1]
Volume of small tank with acetylene gas ,
Pressure of the acetylene gas inside the tank = 
..[2]
Considering both the gases having same temperature T, [1]=[2]



77.14 atm of pressure should be of an acetylene in the tank.
A is true of UV rays.
B is true not of UV rays but rather of visible light.
C is true not of UV rays but rather of microwaves. (unless you actually toast your toast in a toaster like a normal person)
D is true not of UV rays but rather of radio waves.