7. a white precipitate being formed after adding barium chloride and dilute hydrochloric acid to a solution shows the presents of...
sulphates
halides
carbonates
nitrates
8. after adding sodium hydroxide to a solution and heating gently, a gas is formed which turns damp red litmus paper blue. what is present?
bromine ions (Br-)
ammonium ions (NH4+)
magnesium ions (Mg2+)
copper carbonate
9. after adding sodium hydroxide to a solution, warming it and adding aluminium powder, ammonia gas is produced. what does this denote the presence of?
carbonates
halides
nitrates
sulphates
10. After adding sodium hydroxide to a solution, a white precipitate is formed which is insoluble in excess sodium hydroxide solution. which two ions could be present?
iron (II) and iron (III) ions (Fe2+ and Fe3+)
calcium (Ca2+) and magnesium (Mg2+) ions
copper (Cu2+) and aluminium (Al3+) ions
aluminium (Al3+) and magnesium (Mg2+) ions
11. the flame colour for calcium is...
golden yellow
no flame colour
brick red
bright red
lilac
green
12. the flame colour for potassium is...
green
brick red
lilac
no flame colour
bright red
golden yellow
13. which is NOT an disadvantage of instrumental analysis?
only work at very high pressure
expensive
specialist training needed
only comparable with known subjects
14. as this is heated the colour changes from white to lemon yellow and back to white as it cools down. what is this?
sodium hydroxide
copper carbonate
zinc carbonate
barium chloride
15. A light green precipitate is formed which slowly turns to brown (looking 'dirty green') after adding sodium hydroxide to a solution. what is present in the solution?
