45.00 mL of unknown calcium hydroxide solution is titrated with 0.450 M standard nitric acid solution. If 41.37 mL of the standard acid solution is required to reach a phenolphthalein endpoint, what is the molarity of the unknown calcium hydroxide solution

0.0207 M

Explanation:

The equation of the reaction is

2HNO3(aq) + Ca(OH)2(aq)> Ca(NO3)2(aq) + 2H2O(l)

concentration of  acid CA= 0.45 M

concentration of base CB = ???

Volume of acid VA = 41.47 ml

Volume of base VB = 45.00 ml

Number of mole of acid NA = 2

Number of moles of base NB=1

Given;

CAVA/CBVB =NA/NB

CAVANB =CBVBNA

CB = CAVANB/VBNA

CB= 0.45 * 41.47 * 1/45.00 *2

CB = 0.0207 M