Title DPP-9 SOLUTION.pdf ✅

CLASS : XIth SUBJECT : CHEMISTRY DATE : DPP No. : 9 2 (a) 2NaHCO3 + MgCl2⟶MgCO3 + 2NaCl + H2O 3 (c) K2O is pot. Oxide; K2O2 is pot. Peroxide; KO3 is ozonide. 4 (a) It is reason for the given fact. 5 (d) Follow text. 6 (a) CaCl2 is hygroscopic in nature. 7 (a) KI reacts with Pb 2+, Hg 2+ and Cu 2+ to give insoluble iodides of Pb, Hg and Cu. 8 (c) Both Be and Al are rendered passive due to the formation of inert, insoluble and imprevious oxide layer on their surface. 10 (c) K2O + H2O⟶2KOH Alkali 11 (c) Mg is found in sea water. 12 (b) The formula of ′A′is M3N. It suggests that M is a monovalent metal. 6Li + N2 →2Li3N ∆ 6 Li + N2 (M) (A) lithium nitride Li3N + 3H2O →3LiOH + NH3 (B) CuSO4 + 4NH3 →[Cu(H3 )4 ]SO4 blue solution Hence, M and B are Li and NH3 respectively. Topic :- THE S-BLOCK ELEMENTS Solutions
13 (b) Salts of calcium are used in the form of manure e.g., triple superphosphate of lime [Ca(H2PO4 )2H2O]. 14 (b) Mixture of MgCl2 and MgO is called Sorel’s cement. It is MgCl2 . 5MgO .xH2O. 15 (a) The electropositive character increase down the gp. and decreases along the period. 16 (c) In Castner process the process of extracting sodium metal can be written as, 4NaOH ⟶4Na + + 4OH ― Its oxidation reaction which occurs at anode is 4OH ―⟶2H2O + O2 + 4e ― 17 (a) Calcium is manufactured by the electrolysis of a molten mixture of calcium chloride containing some CaF2. CaCl2 ⇌Ca 2+ + 2Cl ― Ca 2+ + 2e ― →Ca (at cathode) 18 (d) 3Mg + N2⟶Mg3N2 2Mg + O2⟶MgO 2Mg + CO2⟶2MgO + C 19 (d) Baking soda is NaHCO3. 20 (a) The basic character of oxides decreases along the period.
ANSWER-KEY Q. 1 2 3 4 5 6 7 8 9 10 A. C A C A D A A C D C Q. 11 12 13 14 15 16 17 18 19 20 A. C B B B A B A D D A