Q21.150CP - Chemistry: Molecular Nature Of Matter And Change

Question

Use Appendix D to create an activity series of Mn, Fe, Ag, Sn, Cr, Cu, Ba, Al, Na, Hg, Ni, Li, Au, Zn, and Pb. Rank these metals in order of decreasing reducing strength, and divide them into three groups: those that displace ${\mathbf{H}}_{\mathbf{2}}$  from water, those that displace ${\mathbf{H}}_{\mathbf{2}}$  from acid, and those that cannot displace ${\mathbf{H}}_{\mathbf{2}}$ .

Step-by-Step Solution

Answer

Li, Ba, Na, Al, Mn, Zn, Cr, Fe, Ni, Sn, Pb, Cu, Ag, Hg, Au are the elements in decreasing order.

Mn, Al, Na, Ba, and Li may all remove hydrogen from water.

Mn, Al, Na, Ba, Li, Zn, Cr, Fe, Ni, Sn, and Pb are among the metals that can be displaced by acid.

Cu, Hg, Ag, and Au are unable to displace hydrogen.

Step 1: Chemical reaction

Chemical synthesis or, alternatively, chemical breakdown into two or more separate chemicals occurs when one component interacts with another to generate a new material. These processes are known as chemical reactions, and they are generally irreversible until followed by other chemical reactions.

Step 2: Rank the metal

The standard reduction potentials are listed in Appendix D:

$\begin{array}{l}Mn -1.18\\ Fe -0.44\\ Ag 0.80\\ Sn -0.14\\ Cr -0.74\\ Cu 0.34\\ Ba -2.90\\ Al -1.66\\ Na -2.71\\ Hg 0.85\\ Ni -0.25\\ Li -3.05\\ Au 1.50\\ Zn -0.76\\ Pb -0.13\end{array}$

As, the ability to be a reducing agent increases with the negative standard potential, the arrangement in decreasing strength will be: Li, Ba, Na, Al, Mn, Zn, Cr, Fe, Ni, Sn, Pb, Cu, Ag, Hg, Au.

In order to determine which metals may displace hydrogen in water, they must have a lower reduction potential than water oxidation,  . 

Mn, Al, Na, Ba, and Li have an   value of less than  V.

Metals having   less than the voltage of the normal hydrogen potential, which is equal to  , can displace hydrogen from acid.

Mn, Al, Na, Ba, Li, Zn, Cr, Fe, Ni, Sn, and Pb are the metals in question.

 

Cu, Ag, Hg, and Au are examples of metals with reduction potentials larger than   that cannot displace hydrogen.

Therefore, we get:

Li, Ba, Na, Al, Mn, Zn, Cr, Fe, Ni, Sn, Pb, Cu, Ag, Hg, Au in decreasing order.

Mn, Al, Na, Ba, and Li all have the ability to remove hydrogen from water.

Mn, Al, Na, Ba, Li, Zn, Cr, Fe, Ni, Sn, Pb, Fe, Ni, Sn, Pb, Fe, Ni, Sn, Pb, Fe, Ni,

Cu, Hg, Ag, and Au cannot displace hydrogen.