Transition metal precipitation reaction colours Flashcards
What colour of Mn^7+ in water?
purple
What is the colour of Cu^2+ in water?
blue
What colour is Fe^2+ in water?
pale green
What colour is Cr^6+ in water?
orange
What colour change takes place when Cu^2+ reacts with aqueous NaOH?
pale blue to blue gelatinous precipitate
What colour change takes place the Cu^2+ reacts with aqueous ammonia?
pale blue to blue gelatinous precipitate
What happens if you add an excess of ammonia to Cu^2+?
blue gelatinous precipitate will re-dissolve and form a deep blue solution
What colour change takes place when Fe^2+ reacts with aqueous NaOH?
- pale green solution forms a green precipitate
- turns rusty brown at its surface on standing in air
What colour change takes place when Fe^2+ reacts with aqueous ammonia?
- dark green precipitate
- turns rusty brown at its surface on standing in air
What colour change takes place when Fe^3+ reacts with aqueous NaOH?
pale yellow solution forms a rusty brown precipitate
What colour change happens when Fe^3+ reacts with aqueous ammonia?
rusty brown precipitate is formed
What colour change happens when Mn^2+ reacts with aqueous NaOH?
- pale pink solution turns into brown precipitate
- darkens in air as it oxidises
What colour change happens when Mn^2+ reacts with aqueous ammonia?
- pale pink solution turns into a brown precipitate
- darkens in air as it oxidises
What colour change takes place when Cr^3+ reacts with aqueous NaOH?
-green solution turns into a green precipitate
What colour change takes place when Cr^3+ reacts with aqueous ammonia?
-green solution turns into a green precipitate
