Which reaction can be easily reversed? A dissolving zinc in hydrochloric acid
B fermenting glucose with yeast
Cheating hydrated cobalt(II) chloride
D the rusting of an iron nail

(Help!)

c

Explanation:

A / B / D are chemical changes

while C is physical change

which is easier to be reversed

as

in dissolving Zn in HCl

H2 gas evolve

glucose fermentation

CO2 gas evolve

Iron rusting produce Fe(OH)3

all produces new substances

thats why the considered to be chemical changes

in chemistry, a solution’s concentration is how much of a dissolvable substance, known as a solute, is mixed with another substance, called the solvent. the standard formula is c = m/v, where c is the concentration, m is the mass of the solute dissolved, and v is the total volume