The reaction for the combustion of acetylene is shown. Explain why this reaction is a redox reaction by identifying the oxidation numbers that change, what is oxidized, what is reduced, and what happens to the electrons during the reaction. 2C2H2 + 5O2 → 4CO2 + 2H2O

2 C2H2 (g) + 5 O2 (g) → 4 CO2 (g) + 2 H2O (l)

Explanation:

Redox reaction: In this type of reaction, oxidation and reduction reaction occurs simultaneously in same chemical reaction.

2C_2H_2+5O_2\rightarrow 4CO_2 + 2H_2O2C

2

H

2

+5O

2

→4CO

2

+2H

2

O

This reaction is a redox reaction :

Removal of hydrogen or addition of oxygen is termed as oxidation. in above reaction, removal hydrogen from acetylene gives carbon-dioxide.

Removal of oxygen or addition of hydrogen is termed as reduction. in above reaction, removal of one oxygen atom from oxygen molecule with addition of two hydrogen atoms gives water

The oxidation number of carbon in acetylene is -2.

The oxidation number of carbon in carbon-dioxide= +4

Oxidation number of carbon increases after the reaction which means that carbon is getting oxidized.

The oxidation number of oxygen in oxygen gas = 0

The oxidation number of oxygen in water = -2

Oxidation number of oxygen decreases after the reaction which means that oxygen is getting reduced.

The electrons released during oxidation are transferred to the species which are undergoing reduction reaction.

the answer is the

n2(g) + 3h2-> 2nh3(g)   this is the balanced equation

note the mole ratio between n2, h2 and nh3.   it is 1 : 3 : 2   this will be important.

moles n2 present = 28.0 g n2 x 1 mole n2/28 g = 1 mole n2 present

moles h2 present = 25.0 g h2 x 1 mole h2/2 g = 12.5 moles h2 present

based on mole ratio, n2 is limiting in this situation because there is more than enough h2 but not enough n2.

moles nh3 that can be produced = 1 mole n2 x 2 moles nh3/mole n2 = 2 moles nh3 can be produced

grams of nh3 that can be produced = 2 moles nh3 x 17 g/mole = 34 grams of nh3 can be produced

note:   the key to this problem is recognizing that n2 is limiting, and therefore limits how much nh3 can be produced.