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Thursday, October 8, 2020
What are the number of sigma bond, pi-bond and lone pair in the lewis dot structure of SO3 ?
Which is best known pseudohalide ?
The best
known pseudohalide is CN-.This resembles Cl- , Br- and I- in the following
respects:
(i) It forms an acid, HCN.
(ii) It can be oxidised to (CN)2 molecule.
(iii) It forms insoluble salts with Ag+, Pb2+ and Hg22+
(iv) It forms large number of complexes
similar to halide complexes,
e.g. [Cu (CN)4]2-
and [CuCl4]2, [Co(CN)6]3- and [CoCl6]3-
(v) Inter-pseudohalogen compounds
ClCN, BrCN and ICN can be formed.
(vi) AgCN is insoluble in water but
soluble in ammonia like AgCl.
What is structure of Beryllium chloride ?
Beryllium chloride a colorless crystal. it is deliquescent and soluble in water and ethanol. And its melting, boiling point are 405 °C ,520 °C respectively. Beryllium is a discrete molecule (BeCl2-dicoordinate) in gaseous state but in solid state it forms a 1-dimensional chain (tetra-coordinated) beryllium via chlorine bridges bond. It is a as Lewis acid monomeric (BeCl2) form and is used as a catalyst for (FCR) Friedel-Crafts reactions.
Related Questions:
(1) What is structural feature of Beryllium halides ?
(2) Why both BeCO3 and BeSO4 are unstable to heat, while BaCO3 and BaSO4 are stable.Explain?
(3) What are the distinct structural features of sodium and potassium bicarbonates ?
(4) Why potassium carbonate cannot be prepared by Solvay process?
(5) Why are Group first elements called alkali metals?
(6) What is the most reactive alkali metal and why?
(7) The alkali metals have low densities. Explain. ?
(9) Which alkali metal is most abundant in earth’s crust?
(10) Why is the density of potassium less than sodium?
(11) Why is lithium the strongest reducing agent in the periodic table?
(12) Name the metal which floats on water without any apparent reaction with it.
(13) Which is softer – Na or K and why?
(14) What makes sodium highly reactive?
(15) Why Li forms only oxides and not stable peroxide or superoxides ?
(16) Why LiCl is predominantly covalent while NaCl is ionic?
(17) Why alkali metals are normally kept in kerosene oil?
(18) Why Lithium is store in paraffin wax, not in kerosene oil unlike other alkali metals?
Wednesday, October 7, 2020
What is "Zeolite's" ?
Zeolite ia Sodium, Potassium salt of alumino silicate. The general formula of Zeolite is as
M x/n [(AlO2)x (SiO2)] · mH2O.
Where M= Na+, K+, NH4+, Li+, Ca+2, Mg+2
Examples: Na2[(AlO2)12 (SiO2)]·27H2O
Zeolite’s have truncated Octahedral structure.
Zeolite’s are molecular sieves (Chalni) , are used to removed hardness of water and sulphate unit from detergents.
Related Questions:
What is basicity of "Boric acid" ?
H3BO3 is soluble in water and behaves as weak monobasic acid. It does not donate protons but rather it accepts OH- .Therefore it acts as a Lewis acid [B(OH)3] .It is not a proton donor because it accept lone pair or hydroxyl ion from water.
Related Questions:
Why Ga has small size than Al exceptionally
Why aqueous solution of borax reacts with two moles of acids ?
What is structure of solid Ortho Boric acid ?
What is the structure of trimetaboric acid and trimetaborate ion?
Why Borazine is more reactive than benzene towards Electrophic Aromatic substitution reactions ?
Why Borazine (B3N3H6) is also known as inorganic benzene ?.
Why B-F bond length in BF3 is shorter (130 pm) than B-F bond Iength in BF4- (143 pm)?. Explain.
Why B-F do not exist as dimer?. Explain.
Although anhydrous aluminium chloride is covalent but its aqueous solution is ionic in nature. Why?
Why Boric acid become strong acid in the presence of cis 1,2-diol or 1,3-diol ?
