Regarding galvanic cells, iron sheets and zinc sheets are immersed in dilute sulfuric acid and conne

Because zinc is more reactive than iron, dilute sulfuric acid is not oxidizing, so we see the zinc sheet gradually dissolving and bubbles coming out of the surface of the iron sheet. Because according to the principle of galvanic cells, zinc and iron are connected with wires and inserted into the electrolyte solution to form galvanic cells; Because zinc is more active than iron, zinc reacts with dilute sulfuric acid first, and transfers 2mol electrons for every 1mol of zinc in the reaction, and the metal zinc transfers electrons to the iron sheet, and the hydrogen ions in the solution gather near the iron sheet, the hydrogen ions get electrons, which are reduced to hydrogen and escape, and the zinc is oxidized into zinc ions into the solution until the zinc is completely dissolved or the sulfuric acid is completely reacted. Iron will not react with dilute sulfuric acid until all zinc is dissolved, and after all zinc is dissolved, iron will continue to react with the remaining dilute sulfuric acid because iron is also a pre-hydrogen metal, but iron will not react with dilute sulfuric acid during the reaction process of forming galvanic cells.

In summary, we see the following phenomena: the zinc sheet gradually dissolves, bubbles emerge on the surface of the iron sheet, and an electric current forms between the metal sheet and the wire (which can be measured with an ammeter). Only zinc is dissolving in the two metal sheets, while hydrogen gas escapes from the surface of the iron sheets.

This is a ZN-FE galvanic battery.

The active one is extremely negative, and the inactive one is positive.

In this battery, Zn is more active than FE as the negative electrode.

So the negative zinc loses electrons and becomes zinc ions.

The hydrogen ions in the cathode solution get electrons and turn into hydrogen gas.

In fact, the total reaction is the reaction of zinc and sulfuric acid.

m(zn) = participating in the reaction

For every 65g of Zn, the number of electrons transferred = 2Na, so the number of electrons transferred by Zn = *2=, so the volume of H2 precipitated on the copper surface v=

Number of electrons passing through the wire =

n(zn)=

zn-2e+2h=h2+zn2-

5L (Biao Wei frankly changed the head?) refers to the Tung) = electron.

zn---cu---h2---2e

x=y=Hydrogen is precipitated from the surface of the copper, and the electrons pass through the first bridge in the wire.

Because zinc is more reactive than iron, dilute sulfuric acid.

No, it doesn't. Oxidation.

So we see that the zinc sheet gradually dissolves and bubbles bubble up on the surface of the iron sheet. Because according to.

Primary batteries. The principle of zinc and iron is inserted with a wire connection.

Electrolyte solution.

later, galvanic cells are formed; Since zinc is more active than iron, zinc reacts with dilute sulfuric acid first, and 2mol of electrons are transferred for each reaction of 1mol of zinc, and metal zinc transfers electrons to iron sheets, while in solution.

Hydrogen ions. Gathered near the iron sheet, hydrogen ions gain electrons and are reduced to hydrogen gas to escape, and zinc is oxidized into it.

Zinc ions. into solution until the zinc is completely dissolved or the sulfuric acid is completely reacted. After all zinc is dissolved, iron will continue to react with the remaining dilute sulfuric acid because iron is also a pre-hydrogen metal, but iron does not react with dilute sulfuric acid during the reaction process of forming galvanic cells.

To sum up, the phenomena we see are: the zinc sheet gradually dissolves, bubbles emerge on the surface of the iron sheet, and an electric current is formed between the metal sheet and the wire (which can be used.

Ammeter. measurements). Only zinc is dissolving in the two metal sheets, while hydrogen gas escapes from the surface of the iron sheets.

By the total reaction of the battery Zn + H2SO4 = ZnSO4 + H2 the amount of Zinc and the amount of hydrogen is equal, N(Zn) =

v(h2) = under standard condition).

The zinc sheet is the negative electrode that undergoes an oxidation reaction and turns into divalent zinc ions into the solution, and the mass of course decreases.

The copper sheet is connected with the zinc sheet with a wire and inserted into the dilute balance Biqing sulfuric acid, which meets the composition conditions of the galvanic battery, so zinc, copper and dilute sulfuric acid constitute the galvanic battery, and the zinc sheet is prone to oxidation reaction and is used as a negative continental electrode, then the copper is used as the positive electrode, and the positive electrode obtains hydrogen ions and her electrons are reduced by the electron, so D is selected

(1) Zinc sheets, silver sheets, and dilute sulfuric acid constitute galvanic cells, zinc is used as the negative electrode, and the zinc loses electrons on the negative electrode for oxidation reaction, and the electrode reaction formula is: zn-2e-

zn2+；Silver is used as the positive electrode, and the electrons obtained by hydrogen ions on the positive electrode undergo a reduction reaction, and the electrode reaction formula is 2H+

2e-=h2, when the galvanic cell is working, the cation moves to the positive electrode, in the galvanic cell, the zinc on the negative electrode loses electrons and becomes zinc ions into the solution, resulting in a decrease in mass, and the metal on the positive electrode does not participate in the reaction, so the reduced mass in the device is the mass of zinc, according to the equality of the transferred electrons, the amount of the substance that generates hydrogen is equal to the amount of the substance of zinc, so the volume of the gas generated = (60?47)g

65g mol, so the answer is: oxidation; Cathode; l；

2) The electrolyte of the acid hydrogen-oxygen fuel cell is acid, the positive electrode undergoes a reduction reaction, and the oxygen electrons are generated into water, and the electrode equation is O2

4e-+4h+

2H2O, under alkaline conditions, in the fuel cell, the hydrogen on the negative electrode loses electrons to generate water, and the electrode reaction formula is: 2H2

4oh--4e-

4h2o, so the answer is: o2

4e-+4h+

2h2o； 2h2

4e-+4oh-

4h2o；3) According to the reaction, it can be known that Fe should be the negative electrode, which is oxidized, the positive electrode can be C, Cu, etc., and the electrolyte solution contains Fe3+, which can be ferric chloride or iron sulfate, etc., and the device diagram is <>, so the answer is: <>

Zinc is more active than copper, and when the galvanic cell reaction is formed, zinc is the negative electrode, and the oxidation reaction occurs, and the electrode reaction formula is zn-2e-

Zn2+ copper is the positive electrode, and the reduction reaction occurs, and the electrode reaction formula is 2H+2E-H2, when the wire passes.

electrons, transfer electrons as.

The large amount of zinc loses electrons, and the mass of the zinc sheet is reduced to 1

The volume of hydrogen rolling out of the surface of the copper sheet is silent, so the answer is: ;;

Question D analysis: The more reactive metal in the galvanic cell is the negative electrode, which loses electrons and undergoes oxidation reaction. The electrons are transferred to the positive electrode through the wire, so the cations in the solution move to the positive electrode, and the positive electrode gets electrons, and a reduction reaction occurs.

Zinc is more reactive than copper, so zinc is the negative electrode and loses electrons. Copper is the positive electrode, and the copper ions in the solution get electrons at the positive electrode, so options a, b, and c are all correct, and d is incorrect, Cu2+ in the solution moves to the positive electrode, and the answer is D.

Comments: The common test points in the college entrance examination are the examination of basic test questions, and they are not very difficult. It focuses on students' understanding of the principle of galvanic batteries, especially the electrode name and electrode reactive writing, with the intention of cultivating students' logical reasoning ability.

Clarity on how galvanic batteries work is the key to answering the question.

A. In the galvanic cell composed of zinc sheet-copper sheet-dilute sulfur white acid solution, the more active metal zinc is used as the negative electrode, the DAO electrode quality is reduced, the copper is used as the positive electrode, and the hydrogen ions are electrons to produce hydrogen, so A is wrong;

B. In the galvanic cell composed of zinc sheet-copper sheet-dilute sulfuric acid solution, the battery reaction is Zn+H2SO4=ZnSO4+H2, which consumes sulfuric acid and generates zinc sulfate, so the pH of the solution increases, and the concentration of Zn2+ increases, so B is correct;

c. SO4 in solution

2- Move to the negative pole, so c is wrong;

D. Electrons flow from the negative electrode to the positive electrode, that is, from the zinc sheet to the copper sheet, so D is correct and AC is chosen