24.0 mL of a 0.120 M Ca(OH)2 solution is required to titrate 160 mL of an HCl solution to its equivalence point. Find the moles of HCl and its concentration in molarity.

the balanced reaction is as follows;
Ca(OH)₂ + 2HCl ---> CaCl₂ + 2H₂O
stoichiometry of Ca(OH)₂ to HCl is 1:2
number of moles of Ca(OH)₂ reacted = 0.120 mol/L x 0.0240 L = 0.00288 mol according to molar ratio of 1:2 number of HCl moles reacted = twice the number of Ca(OH)₂ moles reacted
number of HCl moles reacted = 0.00288 mol x 2 = 0.00576 mol
number of HCl moles in 160 mL - 0.00576 mol
therefore number of HCl moles in 1000 mL - 0.00576 mol / 160 mL x 1000 mL = 0.036 mol
molarity of HCl = 0.036 M

RomeliaThurston RomeliaThurston · Answer 2 · 2019-04-29T07:50:54+02:00

Answer: The molarity of HCl is 0.036 M and moles of HCl is 5.76 moles.

Explanation:

To calculate the molarity of HCl used to titrate [tex]Ca(OH)_2[/tex], we use the equation:

[tex]n_1M_1V_1=n_2M_2V_2[/tex]

where,

[tex]n_1,M_1\text{ and }V_1[/tex] is the n-factor, molarity and volume of calcium hydroxide.

[tex]n_2,M_2\text{ and }V_2[/tex] is the n-factor, molarity and volume of hydrochloric acid.

We are given:

[tex]n_1=2\\M_1=0.120M\\V_1=24mL\\n_2=1\\M_2=?M\\V_2=160mL[/tex]

Putting values in above equation, we get:

[tex]2\times 0.120\times 24=1\times M_2\times 160\\M_2=0.036M[/tex]

Now, to calculate the number of moles, we use the equation:

[tex]\text{Molarity}=\frac{\text{Number of moles}}{\text{Volume}}[/tex]

Molarity of HCl = 0.036 mol/mL

Volume of HCl = 160 mL

Putting values in above equation, we get:

[tex]0.036=\frac{\text{Number of moles}}{160}\\\\\text{Number of moles of HCl}=5.76mol[/tex]

Hence, the molarity of HCl is 0.036 M and moles of HCl is 5.76 moles.