Title DPP-1 SOLUTION.pdf ✅

CLASS : XIth SUBJECT : CHEMISTRY DATE : DPP No. : 1 1 (b) Na2S2O3 . 5H2O (Hypo). It is called photographer’s fixer because it removes the excess AgBr in the form of soluble silver complex. 2 (c) For an ionic compound to be soluble in water its hydration energy should be more than its lattice energy. 3 (c) Na2S2O3 + AgBr Unexposed ⟶Na3Ag(S2O3 )2 +NaBr The property is used for fixing in photography. 4 (d) Na2S2O3 reacts with AgBr (photography) and with I2 (iodometric and iodimetric titrations). 5 (b) Magnesium sulphate heptahydrate [MgSO4 . 7H2O] is called epsom salt. 6 (d) It is a reason for given fact. 7 (b) CaO + H2O⟶Ca(OH)2 +Energy (heat + sound) 8 (d) Sodium sulphate decahydrate (Na2SO4 . 10 H2O) is also known as Glauber’s salt. 9 (a) Dead burnt is CaSO4. 10 (a) 3Ca(OH)2 + 2Cl2⟶Ca(OCl)2 ∙ CaCl2 ∙ Ca(OH)2 ∙ H2O(or CaOCl2) 11 (a) Baking soda is sodium bicarbonate. 12 (b) Na is basic in nature and forms basic oxides. Topic :- THE S-BLOCK ELEMENTS Solutions
13 (d) NaCl as deposits on sea shores. 14 (d) Ba and Ra on burning in air forms peroxides (MO2). Rest all give oxides (MO). 15 (b) Due to anodic reaction as: 2Cl ―⟶Cl2 +2e. 16 (c) It is a fact. 17 (a) Mg(HCO3 )2 ∆ MgO + H2O + 2CO2 aqueous solution of (products) magnesium bicarbonate 18 (a) Metal M is Be. BeO + H2O ⟶Be(OH)2. Be(OH)2 + 2NaOH ⟶Na2BeO2 + 2H2O Soluble 19 (a) All metals show metallic bonding involving oscillation of electrons in them and thus, are good conductor of heat and electricity.
ANSWER-KEY Q. 1 2 3 4 5 6 7 8 9 10 A. B C C D B D B D A A Q. 11 12 13 14 15 16 17 18 19 20 A. A B D D B C A A A D