D. Noble Gases
Hope this helps!
Yes, the more decimal places in a number mean that it is more accurate :3
Answer:
Electric current
Hydrogen and oxygen gas
Explanation:
Electrolysis is defined as a method of separation whereby an electric current is introduced into compounds to separate them . The electric current used here is a direct electric current (DC) and it makes the compound to be spit into its' component elements.
Now, in the case of water like it says in the question. Water is a mixture of hydrogen and oxygen gas. Thus, when electric current is passed through water which has an Electrolyte, it makes the water to decompose into its compound elements which are hydrogen and oxygen.
We know the formula of the density:
ρ =

;
So the mass will be equal to:
m = ρ * V = 2.70 * 21.3 = 57,51 g =
57510 mg of substance.
So the answer is 57510.