QA Flashcards
Colour of Iron II Oxide (FeO)
Black
Colour of Iron III Oxide (Fe2O3)
Reddish-Brown
(yellowish brown if lower conc.)
Colour of Copper II Oxide (CuO)
Black
Colour of Copper I Oxide (Cu2O)
Reddish-Brown
Colour of Copper II Cabonate (CuCO3)
Green
Usual colour of Copper II salts (eg, CuSO4, Cu(NO3)2, …)
Blue
Colour of Copper II Chloride (CuCl)
Bluish-green
Test for Fe2+ ions in aq NaOH?
Dirty green ppt, insoluble in excess aq NaOH
Test for Fe3+ ions in aq NaOH?
Reddish-brown ppt, insoluble in excess aq NaOH
Test for Fe3+ ions in aq ammonia (NH3)?
Reddish-brown ppt, insoluble in excess aq ammonia
Test for Fe2+ ions in aq ammonia (NH3)?
Dirty green ppt, insoluble in excess aq ammonia
Test for Cu2+ ions in aq NaOH?
Light blue ppt, insoluble in excess aq NaOH
Test for Cu2+ ions in aq ammonia?
Light blue ppt, soluble in excess aqueous ammonia giving dark blue solution
Test for Al3+ ions in aq NaOH?
White ppt, soluble in excess aq NaOH giving colourless solution
Test for Al3+ ions in aq ammonia?
White ppt, insoluble in excess aq ammonia
Test for Ca2+ ions in aq NaOH?
White ppt, insoluble in excess aq NaOH
Test for Ca2+ ions in aq ammonia?
No ppt
Test for Pb2+ ions in aq NaOH?
White ppt, soluble in excess aq NaOH giving colourless solution
Test for Pb2+ ions in aq ammonia?
White ppt, insoluble in excess aq NaOH
Test for Zn2+ ions in aq NaOH?
White ppt, soluble in excess giving colourless solution
Test for Zn2+ ions in aq ammonia?
White ppt, soluble in excess giving colourless solution
Test for K+ / Na+ ions in aq NaOH / NH3?
No ppt
Test for ammonium ion in aq NaOH?
Ammonia produced on warming
Test for ammonium ion in aq ammonia?
-
Test for sulfate ion?
Acidify the solution with dilute nitric acid, then add aqueous barium nitrate. White ppt formed.
Test for chloride ion?
Acidify the solution with dilute nitric acid, then add aqueous silver nitrate. White ppt form.
Test for iodide ion?
Acidify the solution with dilute nitric acid, then add aqueous silver nitrate. Yellow ppt form.
Test for nitrate ion?
Add aqueous sodium hydroxide (NaOH) to the metal nitrate, then add aluminium foil/powder. Warm the mixture. Ammonia produced.
Explain the principle of test for nitrate ion?
Nitrate ions are reduced by aluminium [reduction property of metals] in the presence of aqueous sodium hydroxide to form ammonia gas.
Test for carbonate ion? CO3 2-
React with any dilute acid. Effervescence produced and is found to be carbon dioxide.
Test for carbon dioxide gas
Bubble gas into limewater. White ppt produced. When excess CO2, ppt dissolves.
CO2 + Ca(OH)2 —–> CaCO3 + H2O
in excess CO2:
CaCO3 + H2O + CO2 —–> Ca(HCO3)2
Test for ammonia gas
Damp red litmus paper turns blue
Test for chlorine gas
Bleaches damp litmus paper
Test for sulfur dioxide
Acidified potassium manganate (VII) (aq) turns from purple to colourless.
Sulfur dioxide is reducing agent, KMnO7 is oxidising agent. Manganese VII (Mn7+) reduced to Manganese II (Mn2+)
Test for hydrogen
Lighted splint / burning splint. Flame is extinguished with a loud “pop” sound.
Test for oxygen
Glowing splint. Flame is rekindled with placed near mouth of the test tube.
Is Calcium Hydroxide Ca(OH)2 soluble in water?
Slightly
Is Zinc Hydroxide Zn(OH)2 soluble in water?
No
Is Iron II & Iron III Oxide soluble in water?
No
Is Copper II Oxide soluble in water?
No
Action of heat on substances
- Elements react w O2
- Compounds react w O2
- Metal carbonates decompose to form metal oxide and carbon dioxide (except group 1 carbonates)
Colour of solid carbon
Black
Colour of fluorine
Pale yellow gas at rtp
Colour of chlorine
Greenish-yellow gas at rtp
Colour of bromine
Reddish-brown liquid at rtp
Solid & Gas are also reddish-brown
Colour of iodine
Black solid at rtp
Violet vapour
Reddish-brown / yellowish-brown solution depending on concentration
Colour of nitrogen dioxide
Reddish brown gas at rtp
Colour of nitrogen monoxide
Colourless gas at rtp
Colour of carbon monoxide
Colourless gas at rtp
Potassium manganate (VII) solution colour change
Purple to colourless when reduced
Mn7+ to Mn2+
Potassium dichromate (VI) solution colour change
Orange to green
Cr6+ to Cr3+
Universal indicator colour change
Red (pH0) —> Green (pH7) —> Purple (pH 14)
Methyl orange colour change
Orange at <pH4,
Yellow at >pH4
Phenolphthalein
Pink at pH >9
Colourless at pH <9