Which of the following is an oxidation-reduction reaction?
a.) fe2o3 + 3co -> 2fe + 3co2
b.) cuso4 + 2naoh -> cu(oh)2 +na2so4
c.) 2naoh + h2co3 -> na2co3 + 2naoh
d.) pb(no3)2 + na2so4 -> 2nano3 + pbso4

The correct answer is Option a.

Explanation:

Oxidation-reduction reaction or redox reaction is defined as the reaction in which oxidation and reduction reactions occur simultaneously.

Oxidation reaction is defined as the reaction in which a substance looses its electrons. The oxidation state of the substance increases.

Reduction reaction is defined as the reaction in which a substance gains electrons. The oxidation state of the substance gets reduced.

For the given options:

Option A:

On reactant side:

Oxidation state of iron = +3

Oxidation state of carbon = +2

On product side:

Oxidation state of iron = 0

Oxidation state of carbon = +4

The oxidation state of iron reduces from +3 to 0, it is getting reduced. Thus, it is getting reduced and it undergoes reduction reaction. The oxidation state of carbon increases from +2 to +4. Thus, it is getting oxidized and it undergoes oxidation reaction.

Thus, it is considered as redox reaction.

Option B:

The above reaction is double displacement reaction because here exchange of ions takes place.

Option C:

The above reaction is a neutralization reaction because an acid reacts with base to produce salt and water.

Option D:

The above reaction is double displacement reaction because here exchange of ions takes place.

Hence, the correct answer is Option A.

in 1783 cavendish was working with his hydrogen gas and found that when he burned it and condensed the vapor it was water. this was very significant since it disproved the greek theory of elements completely since water was not a simple substance but the product of two gases. it was lavoisier who hearing of the experiment gave cavendish's gas the name hydrogen ("water-producer") and added that hydrogen burned by combining with oxygen and that water was a hydrogen-oxygen combination.

explanation: