Question

Методом электронного баланса подберите коэффициенты в уравнениях реакций. Укажите окислитель и восстановитель, процессы окисления и восстановления. PbS + HNO3 → Pb(NO3)2 + S + NO+ H2O

Answer 1

Method of Electron Balance in Chemical Reactions

The method of electron balance is used to balance chemical equations by ensuring that the number of electrons gained in reduction reactions is equal to the number of electrons lost in oxidation reactions. This method involves assigning oxidation numbers to each element in the reaction and using these numbers to determine the transfer of electrons.

Let's balance the given equation using the method of electron balance:

PbS + HNO3 → Pb(NO3)2 + S + NO + H2O

To balance this equation, we need to assign oxidation numbers to each element:

- The oxidation number of Pb in PbS is +2. - The oxidation number of S in PbS is -2. - The oxidation number of H in HNO3 is +1. - The oxidation number of N in HNO3 is +5. - The oxidation number of O in HNO3 is -2.

Now, let's balance the equation step by step:

1. Balance the atoms other than hydrogen and oxygen:

PbS + HNO3 → Pb(NO3)2 + S + NO + H2O

2. Balance the oxygen atoms by adding water molecules:

PbS + HNO3 → Pb(NO3)2 + S + NO + 2H2O

3. Balance the hydrogen atoms by adding hydrogen ions (H+):

PbS + HNO3 → Pb(NO3)2 + S + NO + 2H2O

4. Balance the charges by adding electrons:

PbS + HNO3 → Pb(NO3)2 + S + NO + 2H2O + 2e-

5. Balance the electrons by multiplying the half-reactions:

PbS + 4HNO3 + 2e- → Pb(NO3)2 + S + 4NO + 2H2O

Now, let's identify the oxidizing agent (oxidant) and reducing agent (reductant) in the reaction:

- The oxidizing agent is the species that gets reduced. In this case, HNO3 is the oxidizing agent because it gains electrons and is reduced to NO. - The reducing agent is the species that gets oxidized. In this case, PbS is the reducing agent because it loses electrons and is oxidized to Pb(NO3)2.

The oxidation process occurs to PbS, which loses electrons and is oxidized to Pb(NO3)2. The reduction process occurs to HNO3, which gains electrons and is reduced to NO.

To summarize: - The oxidizing agent is HNO3. - The reducing agent is PbS. - The oxidation process occurs to PbS. - The reduction process occurs to HNO3.

Please let me know if you need any further clarification or assistance!