Tiêu đề DPP 6 Solutions.pdf ✅

Class : XIIth Subject : CHEMISTRY Date : DPP No. : 6 1 (b) It is a fact. 2 (a) Willemite, a rare zinc silicate mineral, isZn2SiO4. It has trigonal symmetry and is strongly fluorescent green 3 (d) Ag2O is decomposed on simple heating. 4 (a) It is a fact. 5 (c) ___do____ 6 (c) Although presence of CO2 enhances rusting due to formation of more H + 3O ions. 7 (c) Ruby in mineral of aluminium, ie,Al2O3. It does not contain silicon 8 (d) Because all nitrates are water soluble. 9 (d) Roasting is a process in which ore is heated in air to remove Sulphur impurities. 10 (b) Leaching is a chemical method for the concentration of an ore. 12 (b) Cinnabar (HgS) is a sulphide ore, hence it is concentrated by forth floatation process 14 (b) Bauxite (Al2O3.2H2O) is an oxide ore of aluminium 15 (a) Carnallite is an ore of magnesium containing KCl ∙ MgCl2 ∙ 6H2O . 16 (b) Siderite is FeCO3. 17 (b) It is a fact. 18 (c) Corundum (Al2O3) is the combined state of aluminium Topic :- Isolation Elements Solutions
19 (b) _____do_____ 20 (d) Pig iron is the most impure from of iron and contains highest proportion of carbon (2.5- 4%) Malachite →Cu(OH)2.CuCO3 (Cu ore) Zinc blende →ZnS (Zn ore) Bauxite →Al2O3.2H2O (Al ore)
ANSWER-KEY Q. 1 2 3 4 5 6 7 8 9 10 A. B A D A C C C D D B Q. 11 12 13 14 15 16 17 18 19 20 A. B B B B A B B C B D