I think the first blank is "solidity" and second is "object."
Answer: D is the correct answer
Explanation: When there is no insulator surrounding a metal wire then there is nothing to stop the electrons from flowing outside of the wire, This means that anything the wire comes in contact with could get shocked or burnt when there is a current flowing through the wire.
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.
If the difference in electronegativtiy for the atoms in a bond are greater than 0.4,we consider the bond polar, if the electronegativity is less than 0.4, we consider it non polar. if there are no polar bonds, the molecule is non polar.