The question above is incomplete, the full question is given below:
What additional test would be needed to establish the exact position of hydrogen in the activity series of the following elements: magnesium, zinc, lead, copper and silver.
ANSWER
The position of hydrogen on a reactivity series can be determined by its ability to displace oxygen from the oxide of the metal concerned. If hydrogen is more reactive than a metal, it will displace oxygen from the metal oxide and reduce the metal oxide to its metal. If the metal is more reactive than hydrogen, hydrogen will not be able to reduce the metal oxide to its metal.
When a single compound breaks down into two or more compounds or elements in a chemical reaction then it is known as decomposition reaction.
The chemical symbol for sodium carbonate is 
.
The decomposition of sodium carbonate is:
The decomposition of sodium bicarbonate, will result in the formation of sodium oxide, 
and carbon dioxide, 
.
Hence, carbon dioxide, will produce with sodium oxide, on decomposition of .
The ER takes up a lot of space in some cells<span>. The endoplasmic reticulum may be “rough” or “smooth.” ER that has no attached ribosomes is called smooth endoplasmic reticulum. </span>
Blue should be added somewhere. , than yellow, lastly red+black
Blue, oxygen+hydrogen, carbon+oxygen.
Explanation:
TO calculate emperical formula , we need percentage composition of the elements and molecular mass of a specific compound which is already given in the question
then create a table with 1.name of element, 2.percentage given and its atomic mass , 3.no. of moles
( %given/at.mass of element) ... then take the least value in the no. of moles you have found now and divide with each no. of moles value .. to get a simple digit number.
You have got the empirical formula
