Answer: The correct answer is 1.95 M
Explanation:
To calculate the concentration of acid, we use the equation given by neutralization reaction:
[tex]n_1M_1V_1=n_2M_2V_2[/tex]
where,
[tex]n_1,M_1\text{ and }V_1[/tex] are the n-factor, molarity and volume of unknown acid which is HCl.
[tex]n_2,M_2\text{ and }V_2[/tex] are the n-factor, molarity and volume of base which is [tex]Ca(OH)_2[/tex]
We are given:
[tex]n_1=1\\M_1=?M\\V_1=(45.5-0.0)=45.5mL\\n_2=2\\M_2=1.2M\\V_2=(37.5-0.5)=37mL[/tex]
Putting values in above equation, we get:
[tex]1\times M_1\times 45.5=2\times 1.2\times 37\\\\M_1=1.95M[/tex]
Hence, the concentration of unknown HCl solution comes out to be 1.95 M.
