A ..............................
Answer:
Neutral substance is the one that neither exhibits acidic properties nor basic. Such a type of substance has equal no. of hydrogen and hydroxyl ions. Due to the neutrality state these substances do not show changes in the indicators.
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.
I think it’s number 5 and number 9 hopes this helps.