Which reactions are oxidation-reduction reactions? 1. fes(s) + 2hcl(aq) → h2s(g) + fecl2(g) 2. agno3(aq) + nacl(aq) → agcl(s) + nano3 3. 2c3h6(g) + 9o2(g) → 6co2(g) + 6h2o(g) 4. fe2o3(s) + 3co(g) → 2fe(l) + 3co2(g)

The correct answer is Option 3 and Option 4.

Explanation:

Redox reactions are termed as the reactions in which reduction and oxidation reactions occur simultaneously.

Reduction reactions are the ones where a substance gains electrons. The oxidation state of the substance gets reduced.

Oxidation reactions are the ones where a substance looses electrons. The oxidation state of the substance is increased.

Fro the given options:

Option 1:

This reaction is a type of double displacement reaction because exchange of ions takes place.

Option 2:

This reaction is a type of double displacement reaction because exchange of ions takes place.

Option 3:

On reactant side:

Oxidation state of Carbon = +2

Oxidation state of Oxygen = 0

On product side:

Oxidation state of Carbon = +4

Oxidation state of Oxygen = -2

Here, oxidation state of carbon is increasing from +2 to +4. Thus, it is getting oxidized and oxidation state of oxygen is getting reduced from 0 to -2. Thus, it is getting reduced.

Option 4:

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

Here, oxidation state of carbon is increasing from +2 to +4. Thus, it is getting oxidized and oxidation state of iron is getting reduced from +3 to 0. Thus, it is getting reduced.

Hence, the correct answer is Option 3 and Option 4.

mechanics (greek   is that area of science concerned with the behaviour of physical bodies when subjected to forces or displacements, and the subsequent effects of the bodies on their environment. the scientific discipline has its origins in ancient greece with the writings of aristotle and archimedes[1][2][3] (see history of classical mechanics and timeline of classical mechanics). during the early modern period, scientists such as galileo, kepler, and newton laid the foundation for what is now known as classical mechanics. it is a branch of classical physics that deals with particles that are either at rest or are moving with velocities significantly less than the speed of light. it can also be defined as a branch of science which deals with the motion of and forces on objects. the field is yet less widely understood in terms of quantum theory.

explanation:

out of these options:

ability to burn paper

pure sodium reacting violently with water

the boiling point of water

helium does not tend to react with anything

i would say this is a physical property:

helium does not tend to react with anything

why? :

i said helium does not tend to react with anything because well, it reacts to ! but ability to burn paper, pure sodium reacting violently with water, & the boiling point of water are chemical or

physical properties: the properties of a substance that can be observed without changing the chemical makeup of the substance

chemical properties: properties of a substance relating to the chemical nature and reactivity of the substance