What is the conjugate acid of the Brønsted-Lowry base, CH₃NH₂?

The conjugate acid is the CH₃NH₃⁺ (methylammonium)

Explanation:

As every, Bronsted Lowry base the methylamine can accept a proton to water to become, methylammonium.

This is the reaction, where the water is the acid, the methylamine is the weak base and the conjugate base is the hydroxides, while the  methylammonium is the conjugate strong acid.

We say that is strong, because it can react to water, to make hydrolisis so, we can get methylamine again.

CH₃NH₂ + H₂O  ⇄   CH₃NH₃⁺ + OH⁻        Kb

Reaction for the strong conjugate acid

CH₃NH₃⁺  +  H₂O ⇄  CH₃NH₂  +  H₃O⁺      Ka

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