The question is incomplete, here is the complete question:
A 30.0-mL sample of an unknown strong base is neutralized after the addition of 12.0 mL of a 0.150 M HNO₃ solution. If the unknown base concentration is 0.0300 M, give some possible identities for the unknown base. (Select all that apply)
A.) Ca(OH)₂
B.) LiOH
C.) Sr(OH)₂
D.) Al(OH)₃
E.) NaOH
F.) Ba(OH)₂
<u>Answer:</u> The unknown base could be ![Ca(OH)_2,Sr(OH)_2\text{ or }Ba(OH)_2](https://tex.z-dn.net/?f=Ca%28OH%29_2%2CSr%28OH%29_2%5Ctext%7B%20or%20%7DBa%28OH%29_2)
<u>Explanation:</u>
To calculate the number of moles for given molarity of solution, we use the equation:
.......(1)
Molarity of solution = 0.150 M
Volume of solution = 12.0 mL
Putting values in equation 1, we get:
![0.150M=\frac{\text{Moles of nitric acid}\times 1000}{12.00}\\\\\text{Moles of nitric acid}=\frac{0.150\times 12.00}{1000}=1.8\times 10^{-3}moles](https://tex.z-dn.net/?f=0.150M%3D%5Cfrac%7B%5Ctext%7BMoles%20of%20nitric%20acid%7D%5Ctimes%201000%7D%7B12.00%7D%5C%5C%5C%5C%5Ctext%7BMoles%20of%20nitric%20acid%7D%3D%5Cfrac%7B0.150%5Ctimes%2012.00%7D%7B1000%7D%3D1.8%5Ctimes%2010%5E%7B-3%7Dmoles)
Molarity of solution = 0.0300 M
Volume of solution = 30.0 mL
Putting values in equation 1, we get:
![0.0300M=\frac{\text{Moles of unknown base}\times 1000}{30.00}\\\\\text{Moles of unknown base}=\frac{0.0300\times 30.00}{1000}=0.9\times 10^{-3}moles](https://tex.z-dn.net/?f=0.0300M%3D%5Cfrac%7B%5Ctext%7BMoles%20of%20unknown%20base%7D%5Ctimes%201000%7D%7B30.00%7D%5C%5C%5C%5C%5Ctext%7BMoles%20of%20unknown%20base%7D%3D%5Cfrac%7B0.0300%5Ctimes%2030.00%7D%7B1000%7D%3D0.9%5Ctimes%2010%5E%7B-3%7Dmoles)
Mole ratio of acid and base is calculated as: ![\frac{\text{Moles of unknown base}}{\text{Moles of nitric acid}}=\frac{0.9\times 10^{-3}}{1.8\times 10^{-3}}=\frac{2}{1}](https://tex.z-dn.net/?f=%5Cfrac%7B%5Ctext%7BMoles%20of%20unknown%20base%7D%7D%7B%5Ctext%7BMoles%20of%20nitric%20acid%7D%7D%3D%5Cfrac%7B0.9%5Ctimes%2010%5E%7B-3%7D%7D%7B1.8%5Ctimes%2010%5E%7B-3%7D%7D%3D%5Cfrac%7B2%7D%7B1%7D)
Number of
= 2 × number of
ions
So, the unknown base is diprotic in nature.
Hence, the unknown base could be ![Ca(OH)_2,Sr(OH)_2\text{ or }Ba(OH)_2](https://tex.z-dn.net/?f=Ca%28OH%29_2%2CSr%28OH%29_2%5Ctext%7B%20or%20%7DBa%28OH%29_2)