Some good results in for the second test, but many of you need to learn titrations and precipitations. The main question that you fell down on was the one about titration using Hydrochloric and Sulphuric Acid.
As both of these are strong acids, they disociate to the same extent i.e. they both completely split up releasing their hydrogen ions. The question says that both acids are of the same concentration. If you look at the formula for Hydrochloric Acid and the Formula for Sulphuric acid, you can see that when Sulphuric Acid breaks up, it releases 2 Hydrogen ions as it's H2SO4. Hydrochloric Acid only gives out one when it disociates.
Therefore if you use sulphuric rather than hydrochloric acid you only require HALF the volume as it supplies twice as many hydrogen ions.
The test paper can be found by clicking on the following links
Page 1
Page 2
The Mark scheme can be found by clicking on this link
Mark Scheme
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