Which of the following equations describes a single-replacement reaction?

a. 2n2o5 (g) = o2 (g) + 4no2 (g)
b. 2na (s) + cl2 (g) = 2nacl (s)
c. cl2 (g) + 2kl (s) = 2kcl (s) + l2 (g)
d. h2 (g) + br2 (g) = 2hbr (g)

Option (C) is the correct answer.

Explanation:

A chemical reaction in which more reactive metal or substance displaces one less reactive metal or substance then this type of reaction is known as single displacement reaction.

Thus, we can conclude that out of the given options, the reaction equation            

As in this reaction, one chlorine atom replaces one iodine atom hence it is a single displacement reaction.

first, consult an activity series chart to determine if al is more reactive than fe. it is, so it will replace the fe. now, one can continue with the problem.

next, make sure you have a correctly balanced equation.

3feo + 2al ==> 3fe + al2o3

now, determine which reactant (feo or al) is in limiting supply.

moles feo present = 125 g x 1 mole/71.8 g = 1.74 moles

moles al present = 25.0 g x 1 mole/26.98 g = 0.927 moles

since from the balanced equation, it take 3 mol feo for every 2 mol al, al will be limiting.

you can determine this simply by dividing moles of each by their coefficient in the balanced equation. for example: 1.74/3 = 0.58 and 0.927/2 = 0.464. al is less, so it is limiting.

finally, using the stoichiometry in the balanced eq. determine mass of fe that can be produced from 0.927 moles of al.

0.927 moles al x 3 moles fe/2 moles al x 55.8 g/mole = 77.6 g