Well assuming we have all of these, earth
In the reaction Sn(s) + 2H+(aq) → Sn2+ (aq) + H2(g)
from this reaction, we get that Sn loses from 0 to 2 electrons so it's oxidized So it is the reducing agent.
and H gains from 0 to 1 electrons so, it's reduced so ∴ it is the oxidizing agent
As a solution is contained with 11% by mass of sodium
chloride, this will therefore conclude that the 100g of the solution is
composed of the 11g of the sodium chloride. In which, the correct answer would
be specified as letter c.
So, to determine the number of neutrons in atom, we only have to subtract the number of protons from the mass number. Take note that the nucleus of an atom is composed of protons and neutrons. And the number of particles present in the nucleus is referred as mass number (Also, called as atomic mass).