which solution has the lower pH?
a)0.1 M HCL or 0.1 M HC2H3O2?
b)0.1 M NaOH or 0.1 M NH3?
c)0.1 M Na2CO3 or 0.1 M NaCl?
Remember lower pH means more acidic. Go through a reasoning process such as below. It works every time.
a. HCl is a stronger acid than HAc so HCl should be lower for the same concn (as it is here).
b. NaOH is a stronger base than NH3 so OH will be higher than NH3 for the same concn (as it is here). A higher OH means lower H^+ and higher pH.
c.Na2CO3 is hydrolyzed, NaCl is not. So the pH for NaCl is 7.0, that for Na2CO3 gives
CO3^2- + HOH ==> HCO3^- + OH^-
So this reaction is producing OH^- and HCO3^- (OH is strong base and HCO3^- a weak acid) so the solution will be basic which means higher pH.
citric acid solution
a) To determine which solution has a lower pH, we need to compare the acidic properties of HCl (hydrochloric acid) and HC2H3O2 (acetic acid). HCl is a strong acid, while HC2H3O2 is a weak acid. Generally, strong acids have a lower pH than weak acids. Therefore, the solution with HCl (0.1 M HCl) will have a lower pH than the solution with HC2H3O2 (0.1 M HC2H3O2).
b) Similar to the previous question, we need to compare the basic properties of NaOH (sodium hydroxide) and NH3 (ammonia). NaOH is a strong base, while NH3 is a weak base. Typically, strong bases have a higher pH than weak bases. Therefore, the solution with NaOH (0.1 M NaOH) will have a higher pH than the solution with NH3 (0.1 M NH3).
c) Na2CO3 is a basic salt, while NaCl is a neutral salt. A basic salt tends to have a higher pH than a neutral salt. Therefore, the solution with Na2CO3 (0.1 M Na2CO3) will have a higher pH than the solution with NaCl (0.1 M NaCl).
To determine which solution has the lower pH, we need to compare the strength of the acids or bases present in each solution.
a) HCl is a strong acid and HC2H3O2 is a weak acid. In general, strong acids have a lower pH compared to weak acids. Therefore, the solution with HCl (0.1 M HCl) would have a lower pH compared to the solution with HC2H3O2 (0.1 M HC2H3O2).
b) NaOH is a strong base and NH3 is a weak base. Strong bases have a high concentration of hydroxide ions (OH-) and therefore have a higher pH compared to weak bases. So, the solution with NaOH (0.1 M NaOH) would have a higher pH compared to the solution with NH3 (0.1 M NH3). Remember, we are looking for the solution with the lower pH, so in this case, it would be NH3 (0.1 M NH3).
c) Na2CO3 is a salt that can form a weak base solution when dissolved in water. NaCl is a salt that does not significantly alter the pH when dissolved in water. Therefore, the solution with Na2CO3 (0.1 M Na2CO3) would have a higher pH compared to the solution with NaCl (0.1 M NaCl).
So, to summarize:
a) 0.1 M HCl has a lower pH than 0.1 M HC2H3O2.
b) 0.1 M NH3 has a lower pH than 0.1 M NaOH.
c) 0.1 M NaCl has a lower pH than 0.1 M Na2CO3.