Title DPP-2 SOLUTION.pdf ✅

CLASS : XIth SUBJECT : CHEMISTRY DATE : DPP No. : 2 1 (c) Rest all involve use of Na2CO3. 2 (d) It is a reason for given fact. 3 (b) 3I2 + 6NaOH⟶5NaI + NaIO3 + 3H2O (conc.) 4 (c) NaOCl is used as a bleaching agent and sterilising agent. It is formed by the action of Cl2 with cold and dilute NaOH. 2NaOH + Cl2 ⟶NaCl + NaOCl + H2O Cold and dil. 6NaOH + 3Cl2 ⟶5NaCl + NaClO3 + 3 H2O Hot and conc. 5 (d) CaC2O4 is insoluble in acetic acid. 6 (b) Na2CO3 ∙ 10H2O. 7 (c) Na2CO3 + SO2⟶Na2SO3 + CO2 8 (d) Jump in IP is noticed during the change of shell. 9 (b) 2Rb + 2H2O→2RbOH + H2 As we go down the group reactivity with H2O increases ie, Li < Na < K < Rb < Cs Topic :- THE S-BLOCK ELEMENTS Solutions
11 (a) Thiosulphate (S2O 2― 3 ) is oxidised to tetrathionate (S4O 2― 6 ) ion by iodine. I2 + 2S2O 2― 3 ⟶S4O 2― 6 + 2I ― 12 (b) NaOH + CaO is called soda lime. 3 : 1 13 (a) It is a fact and lithopone is used as paint. 14 (a) LiCl is covalent in nature and thus, soluble inorganic solvents. 15 (d) Ca – brick red colour Sr – crimson red Ba – green. 16 (c) Na2S + I2 + Na2SO3⟶Na2S2O3 + 2NaI 17 (d) 6NaOH + 4S ∆ Na2S2O3 + 2Na2S + 3H2O sod. thiosulphate 18 (d) Sodium peroxide reacts with moisture and CO2 of air (when exposed to air) and becomes white due to the formation of NaOH and Na2CO3. 2Na2O2 + 2H2O →4NaOH + O2 2NaOH + CO2 →Na2CO3 + H2O 19 (c) It is a fact. 20 (b) Al 3+ is very good coagulant for negatively charged dispersions in water.
ANSWER-KEY Q. 1 2 3 4 5 6 7 8 9 10 A. C D B C D B C D B C Q. 11 12 13 14 15 16 17 18 19 20 A. A B A D D C D D C B