# Chem

posted by on .

1) Which solution will have the lowest OH-
A) Na2CO3
B) NaHCO3
C) NaCl
D) NaHSO4
E) NH4Cl

2) Which solution will be the strongest base?
A) Na2CO3
B) NaHCO3
C) NaCl
D) NaHSO4
E) NH4Cl

3) Which aqueous solutions are acidic?
A) Na2CO3 and NaHCO3
B) NaCl and NH4Cl
C) NaHSO4 and NH4Cl
D) NaHSO4 and NaHCO3
E) NaHSO4, NaHCO3, and NH4Cl

What is the order of increasing pH (lowest pH) first) of the solutions?
A) Na2CO3 <NaHCO3<NaCl< NH4Cl
B) NaCl < Na2CO3 < NaHCO3 < NH4Cl
C) NH4Cl < NaHCO3 < NaCl < Na2CO3
D) NH4Cl < NaCl < NaHCO3 < Na2CO3
E) Na2CO3 < NaCl < NaHCO3 < NH4Cl

Which solution will have the highest concentration of Na+ ions?
A) Na2CO3
B) NaHCO3
C) NaCl
D) NaHSO4
E) All are equal

If you could include explanations it would be greatly appreciated!

• Chem - ,

1) Which solution will have the lowest OH-
A) Na2CO3
B) NaHCO3
C) NaCl
D) NaHSO4
E) NH4Cl
The lowest OH will be the highest H^+ so which is the strongest acid?
You can go through and eliminate most of these. You know CO3^2- hydrolyzes extensively so you know they are basic due to that.
CO3^2- + HOH ==> HCO3^- + OH^-.
NaHCO3 solution generally have H^+ = sqrt(k1k2) which makes them approximately pH = 8.5
NaCl you know is neutral (but more acid than A or B).
NaHSO4 you know is acid due to k2 of HSO4^-. The NH4^+ of NH4Cl hydrolyzes to produce H3O^+ by
NH4^+ + H2O ==> H3O^+ + NH3 but you know solution of NH4^+ salts are about 5.3 pH or so. So D is the most acid.

• Chem - ,

2) Which solution will be the strongest base?
A) Na2CO3
B) NaHCO3
C) NaCl
D) NaHSO4
E) NH4Cl
My response to #1 should give youthe answers to #2.

• Chem - ,

3) Which aqueous solutions are acidic?
A) Na2CO3 and NaHCO3
B) NaCl and NH4Cl
C) NaHSO4 and NH4Cl
D) NaHSO4 and NaHCO3
E) NaHSO4, NaHCO3, and NH4Cl

A. If Na2CO3 is very basic and NaHCO3 is slightly basic, then a mixture should be acid or basic....?
B. NaCl is neutral; NH4Cl is slightly acid so ....
C.NaHSO4 and NH4Cl. NaHSO4 is quite acid; NH4Cl slightly acid so the mixture will be ......
D. NaHSO4 + NaHCO3 is an acid + base and it gives Na2SO4 + H2O + CO2. Since neither Na^+ nor SO4^2- are hydrolyzed this is neutral
E.NaHSO4 + NaHCO3 + NH4Cl. You know from D that NaHSO4 and NaHCO3 produces a neutral solution. Adding NH4Cl, which you know produces a slightly acid solution, will give a solution that is ......

• Chem - ,

4.
Based on my responses above what do you think. A is not right.

• Chem - ,

5.
Which solution will have the highest concentration of Na+ ions?
A) Na2CO3
B) NaHCO3
C) NaCl
D) NaHSO4
E) All are equal
There is no answer for this one BECAUSE there is no concn listed for any of them. For equal concentrations, which probably is what the asker meant, is A because there are more Na atoms per molecule than any of the others.

• Chem - ,

b
a
c
d
c