Which of the following would for a buffer if added to 250.0 mL of .150 M SnF2?
a).100 mol HCl
b).060 mol HCl
c).040 mol HCl
d).040 mol NaOH
e).040 mol HF
The simple way.
What is a buffer? It is a weak acid and a salt of the weak acid OR a weak base and a salt of the weak base. So you have SnF2 in the problem. That is a salt. All you need to do is to look at the choices Anything other than HF isn't right.Besides, HF is the ONLY weak acid in the list of choices.
HCl doesn't have a Ka listed because it is a strong acid (100% ionized). NaOH, likewise, is a strong base and it is completely ionized.
To determine which of the options would form a buffer, we need to examine the components of each option and see if they can form a buffer solution when added to the given solution (250.0 mL of 0.150 M SnF2).
A buffer solution is formed by combining a weak acid (or its conjugate base) with its conjugate base (or weak acid), which can resist changes in pH when small amounts of acid or base are added.
Let's examine each option:
a) 0.100 mol HCl: HCl is a strong acid, and when added to the SnF2 solution, it will completely ionize to H+ and Cl-. Since HCl is not a weak acid or its conjugate base, it cannot form a buffer solution.
b) 0.060 mol HCl: Similar to option a), this is also a strong acid, so it cannot form a buffer solution.
c) 0.040 mol HCl: Once again, this is a strong acid and cannot form a buffer.
d) 0.040 mol NaOH: NaOH is a strong base, so it cannot form a buffer solution when added to the SnF2 solution.
e) 0.040 mol HF: Here, we have hydrofluoric acid (HF), which is a weak acid. When added to the SnF2 solution, HF will partially ionize to release H+ ions and form the conjugate base F- (from SnF2). Since we have the weak acid HF and the conjugate base F-, this would form a buffer solution.
Therefore, the option that would form a buffer when added to 250.0 mL of 0.150 M SnF2 is option e) 0.040 mol HF.
To determine which of the options would form a buffer when added to the solution of SnF2, we need to consider the properties required for a buffer solution.
A buffer solution consists of a weak acid and its conjugate base (or a weak base and its conjugate acid). Buffer solutions resist changes in pH when small amounts of acid or base are added to them. In order for a buffer to form, we need to find a weak acid and its conjugate base (or weak base and its conjugate acid) among the given options.
Let's evaluate each option:
a) 0.100 mol HCl: HCl is a strong acid, and when it dissociates in water, it does not have a conjugate base. Therefore, HCl does not form a buffer.
b) 0.060 mol HCl: Similarly, HCl is a strong acid and does not have a conjugate base. Therefore, HCl does not form a buffer.
c) 0.040 mol HCl: As mentioned before, HCl is a strong acid and does not have a conjugate base. Therefore, HCl does not form a buffer.
d) 0.040 mol NaOH: NaOH is a strong base and does not have a conjugate acid. Therefore, NaOH does not form a buffer.
e) 0.040 mol HF: HF is a weak acid, and when it dissociates in water, it forms its conjugate base, F-. Therefore, HF and F- can form a buffer.
Based on the options provided, the only compound that can form a buffer when added to the SnF2 solution is 0.040 mol of HF (option e).
Please note that to form an effective buffer, the relative amounts of the weak acid and its conjugate base should be similar, ideally in a 1:1 ratio.