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PRACTICAL CHEMISTRY GASES Neutral Gases 1. H2O 1. White CuSO4 to blue. 2. blue cobalt chloride to pink. 2. H2 Produces a pop sound with a burning splinter. 3. O2 Rekindles a glowing splinter Acidic gases 4. CO2 1.Brisk effervescence. when passed through lime water, turns it milky. 2. No effect on acidified K2Cr2O7 and KMnO4 5. SO2 6. Cl2 7. HCl 8. H2S 9. NO2 1. turns acidified potassium permanganate from pink to colourless 2. turns acidified potassium dichromate from orange to green. Green colour caused by chromium sulphate 1. turns moist blue litmus red and bleaches it. 2.turns moist starch iodide paper blue black. 1.Gives dense white fumes with ammonia NH3 + HCl NH4Cl 2. Forms a white ppt. with AgNO3 AgNO3 + HCl AgCl + HNO3 AgCl is soluble in NH4OH insoluble in dilute acids Rotten egg smelling gas 1. turns moist lead acetate paper silvery black 2. forms a black ppt. with lead acetate solution. Reddish brown fumes Basic Gas 10. NH3 AMBASSADOR SCHOOL 1. Gives dense white fumes with HCl. 2. forms a pale blue ppt. with CuSO4 and deep blue solution in excess. CATIONS - NaOH With drops of NaOH [colour of ppt.] With Excess NaOH [solubility] 1. Ca2+ Milky white ppt. Insoluble 2. Zn2+ Gelatinous white ppt. Soluble to form a colourless soln. 3. Pb2+ Chalky white ppt. Soluble to form colourless solution Coloured ions 4. Fe2+ Dirty green ppt. Insoluble 5. Fe3+ Reddish brown ppt. Insoluble 6. Cu2+ Pale blue ppt. Insoluble Ammonium Hydroxide With drops of NH4OH [colour of ppt.] With Excess NH4OH [solubility] 1. Ca2+ No ppt. ---- 2. Zn2+ Gelatinous white ppt. Soluble to form a colourless soln. 3. Pb2+ Chalky white ppt. Insoluble Coloured ions 4. Fe2+ Dirty green ppt. Insoluble 5. Fe3+ Reddish brown ppt. Insoluble 6. Cu2+ Pale blue ppt. Soluble to form deep blue or inky blue solution. AMBASSADOR SCHOOL ANIONS Test Observation 1. CO32- Add dil.H2SO4, heat A gas with a brisk effervescence is evolved which turns lime water milky and has no effect on KMnO4 and K2Cr2O7. 2. SO32- Add dil.H2SO4, heat A gas with a suffocating odour which turns 1. acidified KMnO4 from pink to colourless 2. acidified K2Cr2O7 from orange to clear green. 3. S2- Add dil.H2SO4, heat 4. SO4 2- Add dil.HCl and BaCl2 soln. Rotten egg smelling gas 1. turns moist lead acetate paper silvery black 2. forms a black ppt. with lead acetate solution. A white ppt. is formed which is insoluble in dil. HCl. 5. Cl- 1.Conc.H2SO4, heat Gives dense white fumes with ammonia 2. Add AgNO3 Forms a white ppt. with AgNO3 3. Add MnO2, Conc.H2SO4, heat 1. Add Cu turnings, conc.H2SO4, heat 2. Add freshly prepared FeSO4 and conc. H2SO4 Greenish yellow gas which turns moist starch iodide paper blue black. Reddish brown fumes. 6. NO3 - Flame Test Metal ion Colour in flame 1. Na+ Golden yellow 2. K+ Lilac 3. Ca2+ Brick red 4. Cu2+ Green AMBASSADOR SCHOOL A reddish brown ring is formed at the junction of two liquids. [ brown compound formed is Nitrosyl ferrous sulphate FeSO4.NO] ACTION OF HEAT 1. CARBONATES MCO3 heat MO + CO2 i. Copper Carbonate CuCO3 light green heat CuO + CO2 black ii. Zinc Carbonate ZnCO3 white heat ZnO + CO2 yellow hot white - cold 2. NITRATES M(NO3)2 heat MO + NO2 + O2 i. Zinc Nitrate 2Zn(NO3)2 white heat 2ZnO + 4NO2 + O2 yellow hot reddish brown fumes white - cold ii. Copper nitrate 2Cu(NO3)2 heat 2CuO + 4NO2 + O2 blue black reddish brown fumes iii. Lead Nitrate 2 Pb(NO3)2 heat 2PbO + 4NO2 + O2 White buff yellow reddish brown fumes Test for Ammonium ion 1. NH4 + Test Observation Add alkali, heat A pungent smelling gas which turns moist red litmus paper blue is evolved. AMBASSADOR SCHOOL
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