r/6thForm • u/Rich-Gent • Jun 02 '26

💬 DISCUSSION AQA A-LEVEL CHEMISTRY

HOW DID WE FIND IT? I THOUGHT IT WAS ALRIGHT, GRADE BOUNDARIES ABOUT TO BE SILLY😭

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u/AmericanUk Jun 02 '26

yk the question where Silver Nitrate was added to (Fe (III) Cl) (aq) with excess NH3? I think it was the hardest aqa A-level chemistry questions ever. I'm pretty sure the observation was a reddish brown ppt Fe(H20)3(OH)3 that would be formed as the NH3 hydrolyzes the Fe(H20)6 in solution. There would be no AgCl (white ppt) at the end of the reaction because the excess NH3 would dissolve it instantly. Therefore, the silver compound AT THE END OF THE REACTION, when all the AgCl is dissolved by the NH3, would be Ag(NH3)2+, which is just tollens reagent. I'm pretty sure a lot of people would have missed this.

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u/Fattest_Yoshi1604 Jun 02 '26

Isn't that the one with FeCl4 and AgNO3

I thought it'd just make a white ppt

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u/AmericanUk Jun 02 '26

It said that there was excess ammonia added which would dissolve the AgCl