1. A pure salt solution can be any of the following except
a. basic
b. buffered ***
c. alkaline
c. acidic
2. You can make a buffer with all the following except
a. weak acid + conjugate base
b. weak base + salt of weak base
c. strong acid + salt of strong acid *** you can't make a buffer when titrating a strong acid or strong base.
d. weak base + conjugate acid
3. Acidosis is a condition where the body fluids are too acidic. If someone with acidosis uses a lot of salt on their food,
a. the excess sodium ions will tend to raise the pH
b. the excess sodium ions will tend to lower the pH ***
c. the excess chloride will change the pH
d. it won't directly affect their pH
I agree with 1.
I think c is your best answer for #2 but technically I don't like any of them. The part I don't like about the c answer is this. If I take a solution of 0.1 M HCl and titrate it with 0.1 M NaOH (or if I just add some NaOH to it), I get some NaCl produced. For the first few mL of NaOH added the pH changes relatively fast; however, for the next tens of mL , say the next 20 or 30 mL, you will have a buffered solution. That is, after the first few mL of the 0.1 M NaOH have been that strong HCl solution acts as much like a buffer as any normal buffer would.
For #3,I'll pass. I know too little about acidosis but I looked on the net and found a number of articles discussing it so you check your answer there.
2. could D also be the answer?
No. Buffers are made with an acid and its salt (which is a) or a base and its salt (which is d) so both a and d are legitimate ways to make a buffer. Answer c is the best answer there; I just wanted to point out strong acids/strong bases have stretches in their titration curves where they act as buffers. Look at the titration curve for a strong acid with a strong base (or the reverse) and see that there a long almost flat line between the beginning and the point about 1 mL or so before the curve starts bending to the end point where the pH hardly changes at all.
I can't copy on this post but I will post just under this with a url to give you that curve for a strong acid vs strong base.
https://www.google.com/search?client=firefox-b-1-d&q=titration+curve+for+strong+acid+vs+strong+base
To get the answer to question 1, you can eliminate the options one by one:
a. A pure salt solution can be basic if it contains a basic salt.
b. A pure salt solution can be buffered if it contains a weak acid and its conjugate base or a weak base and its conjugate acid, which act as a buffer system.
c. A pure salt solution can be alkaline if it contains an alkaline salt.
d. A pure salt solution can be acidic if it contains an acidic salt.
Therefore, the correct answer is b. buffered.
To get the answer to question 2, you can evaluate each option:
a. A buffer can be made by combining a weak acid (which can release protons, H+) with its conjugate base (which can accept protons) to maintain a relatively stable pH.
b. A buffer can be made by combining a weak base (which can accept protons) with the salt of a weak base (which can release protons) to maintain a relatively stable pH.
c. A buffer cannot be made by combining a strong acid (which completely dissociates in water and readily releases protons) with the salt of a strong acid, as it does not have a weak component to maintain pH stability.
d. A buffer can be made by combining a weak base (which can accept protons) with its conjugate acid (which can release protons) to maintain a relatively stable pH.
Therefore, the correct answer is c. strong acid + salt of strong acid.
To get the answer to question 3, you can analyze the given information:
Acidosis refers to a condition where body fluids have an abnormally high level of acidity. If someone with acidosis consumes a lot of salt, it would result in an increase in sodium ions (Na+) in their body fluids.
a. The excess sodium ions will tend to raise the pH: This option is incorrect because an increase in sodium ions would not directly affect the pH. pH is determined by the concentration of hydrogen ions (H+), not sodium ions.
b. The excess sodium ions will tend to lower the pH: This option is correct because an increase in sodium ions would not directly affect the pH, but it may contribute to an increase in the concentration of hydrogen ions, leading to a decrease in pH and further exacerbating the acidity in the case of acidosis.
c. The excess chloride will change the pH: This option is incorrect because chloride ions (Cl-) do not directly impact pH.
d. It won't directly affect their pH: This option is incorrect since, as mentioned earlier, an increase in sodium ions can indirectly contribute to the acidity in acidosis.
Therefore, the correct answer is b. the excess sodium ions will tend to lower the pH.