Answer:
argon and helium
Explanation:
Argon and Helium is belongs to noble gas. Since novel gases are completely filled outer orbital. therefore they are erratic nature. Hence, noble gas are very stable as it neither except electron nor it denote due to it paired of electronic configuration.
Depending on the materials being welded, these atmospheric gases react with welding area and either it reduces the quality of the weld or make the welding more difficult.
Therefore, to protect welding area from atmospheric gases noble gases which are small in size are used.
Thus, argon and helium are used.
There are 1000 mililiters in a liter, so 1000 ml for every liter, you have 5 liters, so:
5L*1000 = 5000 mL
Mass = moles x molar mass
so mass of 6 moles of h2 is: 6×1×2 = 12g
