Given the mass of aluminum sulfide
= 21.0 g
Molar mass of
= 
Calculating the moles of
:

Each mole
has 3 mol S.
Each mole S constitutes 
Calculating atoms of S in 0.14 mol
:

= 
Active immunity will be the answer
Good luck:)
Nh4cl (the oxidation number of N=-3) so it would be the right answer
Answer:
(c) pH = -log [H^+]
Explanation:
pH defines the acidicity or basicity a solution.
pH also refers to hydrogen ion concentration and it is only applied to aqueous solution.
pH ranges from 0 to 14. A pH of 7 is neutral and a pH less than 7 is acidic while a pH higher than basic.
I would go with the cell membrane In this case as the cell membrane is like skin
- Hope you can brainlest this answer