HCl is a strong acid. A solution of sodium chloride should have a pH of:

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HCl is a strong acid. A solution of sodium chloride should have a pH of:

a. less than seven
b. seven
c. more than seven but less than fourteen
d. more than fourteen
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NaCl is a soluble salt in water and there's no effect on [H30+] and [OH-] concentration. lol it stays at 7.
 
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A clarification for joonkimdds.

Values of pH below 1 and greater than 14 are possible. The pH of 37% HCl is-1.1 and a saturated solution of NaOH has a pH of 15.0. The pH scale is not adequate to measure the acidity of most strong acids and of superacids. Superacids, such as HF with SbF5 and HSO3F (fluorosulfonic acid) with SbF5, are acids which are stronger than 100% H2SO4. Instead Ho, the Hammet function is used. On this scale a 1M aqueous solution of nitric or sulfuric acid has an Ho value of 0. Concentrated sulfuric acid has an Ho value of -10. The strongest superacid, HF/SbF3 (50:50) has a value of -23 and is 10e13 times stronger than concentrated sulfuric.

(Interesting stuff but not necessarily useful!)
 
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boulux said:
NaCl is a soluble salt in water and there's no effect on [H30+] and [OH-] concentration. lol it stays at 7.
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isn't soluble salt same as sea water?
sea water is between 8 and 9 pH (according to my bio text book)
 
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HCl was included to mislead you or if you will, to test your understanding of the concept.

The pH of sea water is 8.0-8.2 but it does not come from the NaCl which is present. The basic pH in sea water comes the CaCO3. In the presence of CO2, CaCO3 reacts (in the sea water) to give calcium bicarbonate. At amospheric conditions the pCO2 is 3.5 x 10 ^-4. Even with low Ca ++ of 4.7 x 10 ^-4 (0.019 g/L of Ca) we get a basic solution of pH 8.3.

In water, NaCl ionizes to give Na+ and Cl- . NaCl does not react with water to give NaOH and HCl.
 
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doc toothache said:
HCl was included to mislead you or if you will, to test your understanding of the concept.

The pH of sea water is 8.0-8.2 but it does not come from the NaCl which is present. The basic pH in sea water comes the CaCO3. In the presence of CO2, CaCO3 reacts (in the sea water) to give calcium bicarbonate. At amospheric conditions the pCO2 is 3.5 x 10 ^-4. Even with low Ca ++ of 4.7 x 10 ^-4 (0.019 g/L of Ca) we get a basic solution of pH 8.3.

In water, NaCl ionizes to give Na+ and Cl- . NaCl does not react with water to give NaOH and HCl.
Click to expand...

r u the one who got 30 on DAT!??!!?!
 
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doc toothache said:
HCl was included to mislead you or if you will, to test your understanding of the concept.

The pH of sea water is 8.0-8.2 but it does not come from the NaCl which is present. The basic pH in sea water comes the CaCO3. In the presence of CO2, CaCO3 reacts (in the sea water) to give calcium bicarbonate. At amospheric conditions the pCO2 is 3.5 x 10 ^-4. Even with low Ca ++ of 4.7 x 10 ^-4 (0.019 g/L of Ca) we get a basic solution of pH 8.3.

In water, NaCl ionizes to give Na+ and Cl- . NaCl does not react with water to give NaOH and HCl.
Click to expand...

Wow..good explanation...didn't think of that.
Yes, i thought there was a trap about this question.
But like you said, Na(aq) and Cl(aq)!
 
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joonkimdds said:
This is an easy question to me :D
pH and pOH has to be 7 in pure water.
so adding those two makes 14 and nothing can go more than 14.
if it's more acidic then it goes below 7(up to 0) depends on strength of acid
if it's more basic then it goes above 7(up to 14) depends on strength of base.

ur problem says it's a strong acid so it should go below 7.
if it's super ultra strong then it will have pH of 0 (wait or is it 1 hm...doesn't matter)
anyway b is pure water so it's half acid half basic.
more than saven makes it more basic
more than 14 is impossbile
it's obviously A which is more acidic.
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Dude, It's good that you are very confident, but watch out for these type of questions. I too agree with no change in PH. that HCl is just there for trick us all.
 
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Sorry, you are all wrong.

HCl is a strong acid. Therefore, Cl- is a weak base. weak base in water produces small amounts of OH- ions in solution. The pH will be basic.

C'mon guys, this is a kaplan question. You have the answers already.
 
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This problem illustrates the dangers of getting info from a website like this.

Be careful guys, stick to textbooks and solutions manuals.
 
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HOTTY said:
Sorry, you are all wrong.

HCl is a strong acid. Therefore, Cl- is a weak base. weak base in water produces small amounts of OH- ions in solution. The pH will be basic.

C'mon guys, this is a kaplan question. You have the answers already.
Click to expand...

LOL, we are all dead.... :eek:
 
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hotty, you lost me. can u clarify?

i mean if ur argument is that Cl- acts like a weak base, then wouldn't Na act like a weak acid, cancelling each other out?

but i still don't see why Cl- acts like a weak base...i thought NaCl would just dissociate giving Na+ and Cl- ions
 
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HOTTY said:
Sorry, you are all wrong.

HCl is a strong acid. Therefore, Cl- is a weak base. weak base in water produces small amounts of OH- ions in solution. The pH will be basic.

C'mon guys, this is a kaplan question. You have the answers already.
Click to expand...

WHAT :eek:
What does the HCl have to do with NaCl solution in water? I don't get it!
 
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1PersianDDS said:
WHAT :eek:
What does the HCl have to do with NaCl solution in water? I don't get it!
Click to expand...

The HCL has nothing to do with the NaCl solution they are speaking of. They merely mention that to try and trick you.
 
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HOTTY said:
Sorry, you are all wrong.

HCl is a strong acid. Therefore, Cl- is a weak base. weak base in water produces small amounts of OH- ions in solution. The pH will be basic.

C'mon guys, this is a kaplan question. You have the answers already.
Click to expand...

lol that's not true and I'm 100% sure of the answer since I'm a chem tutor and I have my notes in front of me...
 
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Hooty was right, it CL- is a conjugate base of HCL a strong acid, therefore a weak base in solution. NA+ can never be a strong acid or even an acid, it has no interaction as far as giving up protons. But Cl- can accept protons and will with the H2O. leaving some Oh- in solution.


Sorry dudes my 24 in gchem speaks for itself.
 
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dddsmack said:
Hooty was right, it CL- is a conjugate base of HCL a strong acid, therefore a weak base in solution. NA+ can never be a strong acid or even an acid, it has no interaction as far as giving up protons. But Cl- can accept protons and will with the H2O. leaving some Oh- in solution.


Sorry dudes my 24 in gchem speaks for itself.
Click to expand...



You have an ego the size of Jupiter.:laugh:
 
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although NaCl solution doesn't give NaOH and HCL, it is still useful as a reference tool when determining whether a salt solution will be acidic or basic.

if Na were to pair up with the OH of water
and Cl were to pair up with the H of water

that woudl result in NaOH (strong base) and HCL (strong acid), which will titrate each other, giving a neutral solution. if the conjugate acids/bases form one strong acid and one weak base, the solution will be acidic, and vice versa.
 
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erichen said:
although NaCl solution doesn't give NaOH and HCL, it is still useful as a reference tool when determining whether a salt solution will be acidic or basic.

if Na were to pair up with the OH of water
and Cl were to pair up with the H of water

that woudl result in NaOH (strong base) and HCL (strong acid), which will titrate each other, giving a neutral solution. if the conjugate acids/bases form one strong acid and one weak base, the solution will be acidic, and vice versa.
Click to expand...

You are 100% correct, my friend...finally! Good job.
 
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Let's assume that HOTTY and dddsmack are correct. Then given equal volumes of 1 M HCl and 1 M NaOH to yield 1 M of NaCl and 1 M H2O we should be able to calculate the pH of the resulting solution. Can you two show us how this is done? If a 1 M solution is not to your liking, please choose any volume and any concentration of HCl and NaOH you wish, but do show the calculation of the final pH.
 
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NaOH was not part of the question. However, it is an integral part in the consideration of the pH of a sodium chloride solution since the salt is the product of a strong acid (HCl) and a strong base (NaOH). The pH of the resulting reaction would have to be the pH of water, which is 7. Those who believe that the pH of a solution of sodium chloride is anyhing other than pH 7 are having a hard time coming to terms with the concept of hydrolysis.

Hydrolysis is the reaction between a salt and water to give an acid and a base. There are 4 possible cases and they are dependent on the hydrolytic behavior of the salts.

1. salts of strong acids and strong bases do not undergo hydrolysis. ( The solutions are simply ionic.) Common cations are Na+, K+, Mg+2, Ca+2, Ba+2, Sr+2; and the anions are Cl-, Br-, I-, ClO4-, BrO4-, ClO3-, NO3-.

2.salts of strong acids and weak bases which give acidic salts (NH4Cl): they contain a cation which undergoes hydrolysis, while the anion is unaffected.
C: NH4+, Al+3, Pb+2, Sn+2; HSO4-, H2PO4-;

HCl + NH4OH=NH4+ = Cl- + H2O

NH4+ + H2O = NH3 + H3O+

3. salts of weak acids and strong bases give basic salts; they contain an anion which undergoes hydrolysis while the cation is unaffected.
F-, Ac_, NO2-, HCO3-, CN-, CO3-, S-2, SO4-, HPO4-2, PO4-3

NaAc =Na+ + Ac-
Ac- + H2O = HAc + OH-

4. salts of weak acids and weak bases can be either neutral acidic or basic depending on the relative strengths of the acid and base. If the Ka>Kb, the solution is acidic; Ka < Kb the solution is basic; Ka=Kb=solution is neutral

see www.science.uwaterloo.ca/~cchieh/cact/c123/salts.html
 
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dddsmack said:
Hooty was right, it CL- is a conjugate base of HCL a strong acid, therefore a weak base in solution. NA+ can never be a strong acid or even an acid, it has no interaction as far as giving up protons. But Cl- can accept protons and will with the H2O. leaving some Oh- in solution.


Sorry dudes my 24 in gchem speaks for itself.
Click to expand...

My 27 says you're wrong, ever hear of a lewis acid? ;) :love:
 
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ugh stupid comp wouldnt let me post, k so ima write this again

if the hcl and cl- were in solution together it would be acidic because the hcl is strong so it has a large ka so it produces a lot of h30+ thus low ph.

but i think this question means that nacl is alone in solution so it dissociates (since it is a salt) and forms Na+ and cl-
the na+ does nothing. Cl- cant hydrolyze because it is a conj base of a strong acid. therefore it doesnt nothing as well.
ph doesnt not change

im pretty sure that thats right.

if you had something like ch3cooNa instead of nacl, then the Ch3coo- is from a weak acid thus when it dissociates into ch3coo- and na+ the conj base can then hydrolyze and form oh- ions, which would be a kb reaction, so something like that would then be basic with a higher ph.
 
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Smooth Operater said:
HCl is a strong acid. A solution of sodium chloride should have a pH of:

a. less than seven
b. seven
c. more than seven but less than fourteen
d. more than fourteen
Click to expand...

It has nothing to do with HCl. HCl is there just to mislead you as doctooth said! NaCl will dissociate in water! Na+ cation is associated with a strong base (NaOH) and Cl- anion is associated with a strong acid (HCl) so these types of cations and anions do not act as acids and bases and only act as salts!!! Thus, the pH of NaCl must be close to 7 or theoratically 7!
 
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this thread is awesome! haha so funny when the above post said my 24 says I am right. hahaha good one buddy. I think in that case, I am going to go with the mr. 27 on gchem. :thumbup:
 
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