What is the concentration of HCl when 25.0 mL of HCl completely reacts with 10.0 mL of 0.1M solution of NH4OH (subscript 4)? Solution steps would be helpful so I can solve other similar problems.
Also, I was looking for the concentration of HCl, not the volume. The equation is:
HCl (aq) + NH4OH (aq) ---> NH4Cl (aq) + H2O (l).
From the equation, we conclude that one mole of HCl will react with one mole of NH4OH, which means that you only have to equate the product of the molarity of the solutions and the respective volumes, i.e.
conc.HCl*25 ml = 0.1M * 10 ml
conc.HCl
= 0.1M*10ml/25ml
= 0.04M
If the ratio of the reactants is not 1:1, an adjustment will be required.
Thanks much! I kept getting 0.4M, but realized that I was multiplying 1M * 10 mL instead of 0.1M.
To determine the concentration of HCl, we first need to use the concept of stoichiometry.
Step 1: Write the balanced chemical equation for the reaction between HCl and NH4OH:
HCl + NH4OH -> NH4Cl + H2O
Step 2: Determine the limiting reagent. This is the reactant that is completely consumed during the reaction, limiting the amount of product that can be formed.
To determine the limiting reagent, we need to compare the moles of each reactant.
First, calculate the number of moles of NH4OH:
moles of NH4OH = volume in liters × molarity
moles of NH4OH = (10.0 mL ÷ 1000) L × 0.1 mol/L
moles of NH4OH = 0.001 mol
Next, calculate the number of moles of HCl:
moles of HCl = volume in liters × molarity
moles of HCl = (25.0 mL ÷ 1000) L × unknown mol/L (let's call it x)
moles of HCl = 0.025x mol
Since the balanced equation has a 1:1 stoichiometric ratio between HCl and NH4OH, the limiting reagent will be NH4OH because it has less moles.
Step 3: Calculate the moles of HCl that reacted:
Using the stoichiometric ratio from the balanced equation, we know that for every 1 mole of NH4OH, 1 mole of HCl reacts. Therefore, the moles of HCl that reacted is also 0.001 mol.
Step 4: Calculate the concentration of HCl:
Concentration (mol/L) = moles/volume (L)
We know that the moles of HCl that reacted is 0.001 mol, and the volume of HCl is 25.0 mL (which equals 0.025 L).
Substituting these values into the formula:
x = 0.001 mol / 0.025 L
x = 0.04 mol/L
Therefore, the concentration of HCl is 0.04 M when 25.0 mL of HCl completely reacts with 10.0 mL of a 0.1M solution of NH4OH.
By following these steps, you should be able to solve similar problems involving concentration calculations.