Transition elements: configuration, occurrence and characteristics
- The reaction that does NOT take place in a blast furnace between 900 K to 1500 K temperature range during extraction of iron is : Answer: 2. Fe ₂ O ₃ + CO → 2FeO + CO ₂ Key idea: The blast furnace has temperature zones: the reduction of Fe₂O₃ to FeO by CO takes place in... 1
- Match List - I with List - II.List - I (Ores): (a) Haematite (b) Magnetite (c) Calamine (d) KaoliniteList - II (Composition): (i) Fe_3O_4 (ii) ZnCO_3 (iii) Fe_2O_3 (iv) [Al_2(OH)_4Si_2O_5]Choose the correct answer from the options given below : Answer: 3. (a) - (iii), (b) - (i), (c) - (ii), (d) - (iv) Key idea: recall ore compositions. Haematite: Fe₂O₃ (iii) Magnetite: Fe₃O₄ (i) Cal... 1
- The maximum temperature that can be achieved in blast furnace is : Answer: 2. upto 2200 K Key idea: this is a recall fact for iron extraction. In the blast furnace the temperature rises from about 500 K at t... 1
- Which one of the following methods can be used to obtain highly pure metal which is liquid at room temperature ? Answer: 3. Distillation Key idea: the metal liquid at room temperature is mercury, which is volatile with a low boiling point (630 K). Disti... 1
- Identify the correct statement from the following : Answer: 4. Pig iron can be moulded into a variety of shapes. Check each statement. (1) Wrought iron is the purest form of iron (about 0.2% c... 1
- Which one is malachite from the following ? Answer: 4. CuCO ₃ .Cu(OH) ₂ Malachite is the green basic copper carbonate CuCO₃· Cu(OH)₂ . CuFeS₂ is copper pyrites and Fe₃O₄ is magnetite.... 1
- Extraction of gold and silver involves leaching with CN^- ion. Silver is later recovered by : Answer: 3. displacement with Zn Key idea: Ag is recovered from the cyanide complex by a more electropositive metal. 2[Ag(CN)₂]^- + Zn → [Zn(... 1
- Match items of Column I with the items of Column II and assign the correct code :Column I: (a) Cyanide process; (b) Froth floatation process; (c) Electrolytic reduction; (d) Zone refiningColumn II: (i) Ultrapure Ge; (ii) Dressing of ZnS; (iii) Extrac… Answer: 1. (iv) (ii) (iii) (i) Key idea: match each process with its use. (a) Cyanide process: extraction of gold (Au), iv. (b) Froth floata... 1