How would the following affect the calculated value of neutralizing power of antacid (make it higher, lower or no effect)?
[The lab uses the back titration technique]
1) The solution mixture of reacted antacid and excess of HCl spattered out the flask during boiling
2) The endpoint was missed because NaOH was added too fast during titration.
3) The mixture of antacid and HCl was heated too long so that some HCl escaped from the solution
4) Some antacid solids were not dissolved in the presence of excess of HCl
To determine how each of the given scenarios would affect the calculated value of the neutralizing power of an antacid, let's analyze them one by one:
1) The solution mixture of reacted antacid and excess of HCl spattering out of the flask during boiling:
In this case, if some of the solution spatters out during boiling, it means that the actual volume of the solution would decrease. As a result, the concentration of the solution would increase, leading to a higher calculated value of the neutralizing power of the antacid.
2) The endpoint was missed because NaOH was added too fast during titration:
When the endpoint is missed, it implies that excess NaOH was added, resulting in overshooting the equivalence point. Consequently, a greater volume of NaOH would be required to reach the endpoint. This would lead to a higher calculated value of the neutralizing power of the antacid.
3) The mixture of antacid and HCl was heated for too long, causing some HCl to escape:
If some of the HCl escapes from the solution due to prolonged heating, it means that the amount of HCl available for neutralization decreases. As a result, a smaller amount of HCl would react with the antacid, leading to a lower calculated value of the neutralizing power of the antacid.
4) Some antacid solids were not dissolved in the presence of excess of HCl:
If some of the antacid solids do not dissolve in the presence of excess HCl, it means that not all of the antacid reacted with the acid. Consequently, the amount of HCl neutralized would be lower than expected, resulting in a lower calculated value of the neutralizing power of the antacid.
In summary:
1) Spattering out of the flask would result in a higher calculated value.
2) Adding NaOH too fast would result in a higher calculated value.
3) Escaping HCl would result in a lower calculated value.
4) Undissolved antacid solids would result in a lower calculated value.