A compound is a substance that consists of 2 or more elements chemically combined in a fixed proportion.
Compounds can be broken down ijt0 simple substances by chemical means but, elements cannot.
Answer:- HBr is limiting reactant.
Solution:- The given balanced equation is:

From this equation, There is 2:6 mol or 1:3 mol ratio between Al and HBr. Since we have 8 moles of each, HBr is the limiting reactant as we need 3 moles of HBr for each mol of Al.
The calculations could be shown as:

= 24 mol HBr
From calculations, 24 moles of HBr are required to react completely with 8 moles of Al but only 8 moles of it are available. It clearly indicates, HBr is limiting reactant.
Reactants would be the missing word in the sentence because they make up the products in a chemical reaction
Answer:
CuSO4 cell will have the greatest amount of deposit among all three. The deposit will occur at the cathode
Explanation:
The valence of the elements in this case is as follows -
Cu - 2e-
Sn - 4e-
Cr - 3e-
CuSO4 cell will have the greatest amount of deposit among all three
The atoms of copper metal will deposit at the cathode. At the cathode, the least number of moles of electrons needed .
Hence, more amount of copper can be extracted out by the electrolyte