I wrote for question 7b, that metal B produce more hydrogen because:
Aluminium has valency of 3 and Chlorine of 1, the formula for Aluminium Chloride is AlCl3, where as for the other 2 metals is MgCl2 and ZnCl2. Therefore 1 Mole of Aluminium will react with more moles of HCl than Zinc and Magnesium, hence producing more hydrogen.
and I wrote the same/similar for 7a where you have to identify metal and explain. Don't know if this will score me the explanation for why Metal B is Aluminium. (I heard many people explained metal B using reaction rate and oxide layer) I hope mine is an alternative answer... And btw why is 7a, the identification and explanation of metals only 5 marks? (I thought it would be 3 pairs of marks)
and what did you write for the explanation for the 2 other metals?
Aluminium has valency of 3 and Chlorine of 1, the formula for Aluminium Chloride is AlCl3, where as for the other 2 metals is MgCl2 and ZnCl2. Therefore 1 Mole of Aluminium will react with more moles of HCl than Zinc and Magnesium, hence producing more hydrogen.
and I wrote the same/similar for 7a where you have to identify metal and explain. Don't know if this will score me the explanation for why Metal B is Aluminium. (I heard many people explained metal B using reaction rate and oxide layer) I hope mine is an alternative answer... And btw why is 7a, the identification and explanation of metals only 5 marks? (I thought it would be 3 pairs of marks)
and what did you write for the explanation for the 2 other metals?