Which of the substances can act both as oxidising and reducing agent?

Answer 1

The terms "reducing agent" and "oxidizing agent" are relative. It seems that you already know this; that depending on the specific reaction, a given compound may be the reducing agent or the oxidizing agent, and in some reactions the same compound is both the oxidizing agent and the reducing agent. It is very important to remember that in an oxidization/reduction reaction, the reducing agent is oxidized and the oxidizing agent is reduced.

Examples: 1) Aldehydes are one example of compounds that can act as reducing agents or oxidizing agents. As reducing agents, aldehydes can reduce Ag(I) in the form of [Ag(NH3)2]+ OH- to Ag metal. They can also reduce Cr(VI) to Cr(III) and Cu(II) to Cu(I). In each case, the aldehyde is oxidized to its corresponding carboxylic acid.

As oxidizing agents, aldehydes (and ketones) can oxidize a hydride (H-) in sodium borohydride or lithium aluminumhydride to H+ as the aldehyde (or ketone) is reduced to an alcohol. Aldehydes and ketones are often used to form carbon-carbon bonds in aldol condensation reactions where a carbanion or an enolate ion attacks the carbonyl carbon of the aldehyde or ketone. In these reactions, the aldehyde or ketone is also reduced to an alcohol.

2) The nitrite anion is another example of a species that can serve as an oxidizing agent or a reducing agent in many reactions. Nitrite (formal charge of N+3) is readily oxidized to nitrate (formal charge of N+5) by the permanganate anion or it can be reduced all the way to ammonia (formal charge of N-3) by hydrogen sulfide. That's an impressive difference of six in the respective nitrogen oxidation states. Like aldehydes and ketones, nitrite can oxidize hydride to H+ in certain borohydride compounds in which nitrite is reduced to N2O, also known as laughing gas.

Answer 2

A series of common examples for red-ox reactions is the reaction of metals with mineral acids. Laboratory experiments such as titration of dichromate ions against oxalic acid are also examples for red-ox reactions.

Answer 3

The compounds which can donate the oxygen as well as can accept the oxygen may act as reducing agents as well as oxidizing agent (depending upon conditions) such compounds include oxides of non metals as SO2, CO, NO etc.

Answer 4

Yes, there are some substances known that can do, but NEVER in the same reaction, with the same reactant that is.

Examples:

(Remember: an oxidant accepts electrons, a reductant donates them)

oxidant: Fe2+ + 2e- --> Fe

reductant: Fe2+ --> Fe3+ + e-

oxidant: Cu+ + e- --> Cu

reductant: Cu+ --> Cu2+ + e-

Even auto redox ouples are known:

At higher temperature CO + CO --> C + CO2

Answer 5

An oxidizing agent is reduced in a chemical reaction by gaining electrons. Some examples are halogens, nitric acid and potassium nitrate.

Answer 6

napthalene powder is reducing or oxidising agenr

Answer 7

because it is gay

Answer 8

So2 , no