Question

What is the concentration of a Ca(OH)2 solution if 15.0 ml of 0.750 M H3PO4 solution is required to completely neutralize 20.0 ml of the Ca(OH)2 solution?

Answer 1

15.0
+0.750
Answer (600

Answer 2

Answer: The concentration of $Ca(OH)_2$ comes out to be 0.843 M.

Explanation:

To calculate the concentration of acid, we use the equation given by neutralization reaction

$n_1M_1V_1=n_2M_2V_2$

where,

$n_1,M_1\text{ and }V_1$ are the n-factor, molarity and volume of acid which is $H_3PO_4$

$n_2,M_2\text{ and }V_2$ are the n-factor, molarity and volume of base which is $Ca(OH)_2$

We are given:

$n_1=3\\M_1=0.75M\\V_1=15mL\\n_2=2\\M_2=?M\\V_2=20mL$

Putting values in above equation, we get:

$3\times 0.750\times 15=2\times M_2\times 20\\\\M_2=0.843M$

Hence, the concentration of $Ca(OH)_2$ comes out to be 0.843 M.