Which of following is a reduction half reaction 2.Which metal is most easily oxidized 3. most easy reduced?

Question

1.a. 2H+ + 2e- --> H2

b. Zn --> Zn2+ + 2e-

c. Na --> Na+ + e-

d. No + 2H2O --> N3- + 4H+ 3e-

2. Which metal most easily reduced

a. slightly active

b. highly active

c. moderatly active

d. inactive metal

3. Of following metals which ions most easily reduced

a. mercury

b. iron

c. aluminum

d. zinc

Thanks for all the help, I am trying to do a summer online class with no teacher, no book and no help. No one I know has a clue about chemistry. Thanks again!!!! :)

Answer 1

Remember, OIL RIG, oxidation is loss and reduction is gain (of electrons)

Therefore, 1 is 'a' as H+ gains electrons.

2. The more reactive a metal is, the easier it is oxidised; the converse must apply, so 'd'.

3. Mercury is the least reactive, so 'a'.

Answer 2

////////////// REDOX reactions

When a paper clip is immersed in a blue solution of "root remover" the shiny clip soon becomes covered in a flaky, red metallic coating. Chemically, what is happening is the following reaction:

Fe + Cu(+2) + SO4(-2) -> Fe(+2) + SO4(-2) + Cu

In plain english, the equation reads "Solid Iron metal plus aqueous Copper Sulfate forms solid Copper metal and aqueous Iron sulfate". "Aqueous" means "dissolved in water". What is happening in terms of chemistry is the Iron is being oxidized and the Copper reduced. When a substance is oxidized, it looses one or more electron. In the case of Iron, the following happens:

Fe -> Fe(+2) + 2e(-)

The english translation is "Iron metal oxidizes to a positive iron ion with a positive charge of +2 and 2 electrons, each with a negative charge".  

The reduction reaction is:

Cu(+2) + 2e(-) -> Cu

The reactions above are two half reactions. REDOX reactions consist of a pair of half reactions. One describes the oxidation and the other describes the reduction.

In a reduction half reaction the electrons are on the left side of the equals sign (chemists use a "-->" symbol). Another clue to a reduction reaction is some pure substance is on the right side. For example:

2H(+) + 2e(-) --> H2

In this reduction, positive hydrogen ions are reduced to pure Hydrogen gas. All the other reactions have electrons on the right side of the equals sign, so they are oxidation half reactions.

In general chemical terms, metals which ordinarily exist as ions are very easily oxidized. Metals which exist as pure solids are easily reduced. For example, Sodium is a metal which is always found as a positive ion. Pure Sodium metal itself is extremely reactive chemically. Gold is very easily reduced and is nearly always found as a pure metal which is very inert chemically. (Chemists refer to Gold as a "noble" metal). Other metals such as iron are somewhere in between these two extremes. Chemists use a chart known as an electrochemical series to calculate the tendancy of elements to be oxidized or reduced.

In the paperclip/root remover example, the Iron was easier to oxidize then the Copper. Therefore, the Copper oxidized the Iron and the Iron in turn reduced the Copper. What is important is the fact there was an exchange of two electrons between the metal atoms. This electron exchange between oxidizing and reducing agents is what make batteries work, like the lead battery in an automobile, for example.

In terms of reducability:

Hg>Fe>Zn>Al

FYI: Chemical atomic symbols are often based on latin terms. Sodium is "Na" which stands for "natrium. Iron is "Fe" for "ferrum". Gold (Au), Silver (Ag), Mercury (Hg), Tin (Sn) and many other metals known for many centuries have atomic symbols based on their latin names.

Also, it might seem very curious that Aluminum is the least easy to reduce, because solid Aluminum metal is so common. However, Aluminum metal is never found naturally and has to be refined using enormous amounts of electricity. It appears inert because it coats itself in a thin film of oxide. This keeps the metal itself from reacting with the environment.