Before adding anything After adding H + After adding OH -1 Color of Cr 2 O 7 -2
ID: 679276 • Letter: B
Question
Before adding anything After adding H+ After adding OH-1 Color of Cr2O7-2 Orange no change yellow Color of Cr2O4-2 Yellow Light orange no change Based on Le Chatlier's Principle a) Explain what happened when acid was added to eachtesttube. b) Explain what happened when base was added to eachtesttube. Before adding anything After adding H+ After adding OH-1 Color of Cr2O7-2 Orange no change yellow Color of Cr2O4-2 Yellow Light orange no change Investigating the reaction: 2CrO42- (aq) + 2 H+(aq) Cr2O72- (aq) +H2O (l) Before adding anything After adding H+ After adding OH-1 Color of Cr2O7-2 Orange no change yellow Color of Cr2O4-2 Yellow Light orange no change Based on Le Chatlier's Principle a) Explain what happened when acid was added to eachtesttube. b) Explain what happened when base was added to eachtesttube.Explanation / Answer
a) Adding acid will favour forward reaction, resulting in amore orange solution to form (MoreCr2O72- ) b) adding base will neutralise the acid, which favours reversereaction, thus a more yellow solution will form (MoreCrO42- )