Question

Which of the following are redox reactions?
P4(s)+10HClO(aq)+6H2O(l)?4H3PO4(aq)+10HCl(aq)
Br2(l)+2K(s)?2KBr(s)
CH3CH2OH(l)+3O2(g)?3H2O(l)+2CO2(g)
ZnCl2(aq)+2NaOH(aq)?Zn(OH)2(s)+2NaCl(aq)
Check all that apply.
Part BFor those reactions that are redox, indicate which elements are oxidized.Express your answers as chemical symbols separated by a commas.Part CFor those reactions that are redox, indicate which elements are reduced.Express your answers as chemical symbols separated by a commas.Part DFor those reactions that are not redox, indicate whether they are precipitation or neutralization reactions.

Answer 1

Answer :

Redox reaction or Oxidation-reduction reaction : It is defined as the reaction in which the oxidation and reduction reaction takes place simultaneously.

Oxidation reaction : It is defined as the reaction in which a substance looses its electrons. In this, oxidation state of an element increases. Or we can say that in oxidation, the loss of electrons takes place.

Reduction reaction : It is defined as the reaction in which a substance gains electrons. In this, oxidation state of an element decreases. Or we can say that in reduction, the gain of electrons takes place.

Precipitation reaction : It is defined as the reaction in which an insoluble salt formed when two aqueous solutions are combined.

The insoluble salt that settle down in the solution is known an precipitate.

(1) $P_4(s)+10HClO(aq)+6H_2O(l)\rightarrow 4H_3PO_4(aq)+10HCl(aq)$

This reaction is a redox reaction.

In this reaction, the oxidation state of 'P' changes from (0) to (+5) that means 'P' lost 1 electron and it shows oxidation reaction and the oxidation state of 'Cl' changes from (+1) to (-1) that means 'Cl' gain 1 electron and it shows reduction reaction.

'P' is oxidized and 'Cl' is reduced.

(2) $Br_2(l)+2K(s)\rightarrow 2KBr(s)$

This reaction is a redox reaction.

In this reaction, the oxidation state of 'K' changes from (0) to (+1) that means 'K' lost 1 electron and it shows oxidation reaction and the oxidation state of 'Br' changes from (0) to (-1) that means 'Br' gain 1 electron and it shows reduction reaction.

'K' is oxidized and 'Br' is reduced.

(3) $CH_3CH_2OH(l)+3O_2(g)\rightarrow 3H_2O(l)+2CO_2(g)$

This reaction is a redox reaction.

In this reaction, the oxidation state of 'C' changes from (-1) to (+4) that means 'C' lost 1 electron and it shows oxidation reaction and the oxidation state of 'O' changes from (0) to (-2) that means 'O' gain 2 electrons and it shows reduction reaction.

'C' is oxidized and 'O' is reduced.

(4) $ZnCl_2(aq)+2NaOH(aq)\rightarrow Zn(OH)_2(s)+2NaCl(aq)$

This reaction is a precipitation reaction in which the two aqueous solution zinc chloride and sodium hydroxide combined to give sodium chloride solution and zinc hydroxide as a precipitate. In precipitation reaction there is no changes in oxidation state of the element.

Answer 2

A redox reaction is said to occur when the oxidation number of reacting species change from left to right.

A redox reaction is in which there is a change in oxidation number from left to right in the reaction. That means that species in a redox reaction either lost or gained electrons.

In the reaction;

P4(s) + 10HClO(aq) + 6H2O(l) ------> 4H3PO4(aq)+10HCl(aq)

We can see that the oxidation number of phosphorus increased from zero to +5. The oxidation number of chlorine decreased from +5 to -1

In the reaction;

Br2(l)+2K(s)-----> 2KBr(s)

The oxidation number of bromine decreased from zero to -1 while the oxidation number of potassium increased from zero to +1.

In the reaction;

CH3CH2OH(l) + 3O2(g)------>3H2O(l) +2CO2(g)

The oxidation number of carbon was increased from -2 to +4 while the oxidation number of oxygen decreased from zero to -2.

In the reaction;

ZnCl2(aq) + 2NaOH(aq)------> Zn(OH)2(s) + 2NaCl(aq)

There is no change in the oxidation number of species from left to right in the reaction. It is rather a precipitation reaction.

Learn more: https://brainly.com/question/1340582