Class 12th Chemistry 2017 Set1 Delhi Board Paper Solution
Write one difference in each of the following:
1) lyophobic sols and lyophilic sol
2) Solution and Colloid
3) Homogeneous catalysis and Heterogeneous catalysis
1) lyophobic sols :
They are those solution in which the dispersed phase has no attraction for the dispersion medium or the solvent. For eg. Dispersion of gold, iron & sulphur in water. They cannot be prepared directly they are prepared by special method only. They are easily precipitated by adding small amount of electrolyte.
lyophilic sol :
They are those solution in which the dispersed phase exhibits a definite affinity for the dispersion medium(liquid) or the solvent.For eg. Dispersion of starch, gum, & protein in water.They cen be easily prepared by directly mixing with liquid dispersion medium. They are quite stable and and not easily precipitated.
2) Solution: Solutions are homogeneous mixture of two or more substance and their particle size is less than10-9 m or 1 nm.
Colloid: These are heterogeneous mixture of two or more particles and their particle size is in between 10-9 to 10-6 m.
3) Homogeneous catalysis:
It is the phenomenon in which reactants and catalyst are present in the same phase.
Heterogeneous catalysis
It is the phenomenon in which reactants and catalyst are present in the different phase.
Popular Questions of Class 12th chemistry
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Give simple chemical tests to distinguish between the following pairs of compounds.
(i) Propanal and Propanone
(ii) Acetophenone and Benzophenone
(iii) Phenol and Benzoic acid
(iv) Benzoic acid and Ethyl benzoate
(v) Pentan-2-one and Pentan-3-one
(vi) Benzaldehyde and Acetophenone
(vii) Ethanal and Propanal
- Q:-
How the following conversions can be carried out?
(i) Propene to propan-1-ol
(ii) Ethanol to but-1-yne
(iii) 1-Bromopropane to 2-bromopropane
(iv) Toluene to benzyl alcohol
(v) Benzene to 4-bromonitrobenzene
(vi) Benzyl alcohol to 2-phenylethanoic acid
(vii) Ethanol to propanenitrile
(viii) Aniline to chlorobenzene
(ix) 2-Chlorobutane to 3, 4-dimethylhexane
(x) 2-Methyl-1-propene to 2-chloro-2-methylpropane
(xi) Ethyl chloride to propanoic acid
(xii) But-1-ene to n-butyliodide
(xiii) 2-Chloropropane to 1-propanol
(xiv) Isopropyl alcohol to iodoform
(xv) Chlorobenzene to p-nitrophenol
(xvi) 2-Bromopropane to 1-bromopropane
(xvii) Chloroethane to butane
(xviii) Benzene to diphenyl
(xix) tert-Butyl bromide to isobutyl bromide
(xx) Aniline to phenylisocyanide
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A 5% solution (by mass) of cane sugar in water has freezing point of 271 K. Calculate the freezing point of 5% glucose in water if freezing point of pure water is 273.15 K.
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A solution of glucose in water is labelled as 10% w/w, what would be the molality and mole fraction of each component in the solution? If the density of solution is 1.2 g mL-1, then what shall be the molarity of the solution?
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Henry's law constant for CO2 in water is 1.67 x 108Pa at 298 K. Calculate the quantity of CO2in 500 mL of soda water when packed under 2.5 atm CO2 pressure at 298 K.
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Calculate the mole fraction of benzene in solution containing 30% by mass in carbon tetrachloride.
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How many mL of 0.1 M HCl are required to react completely with 1 g mixture of Na2CO3 and NaHCO3 containing equimolar amounts of both?
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If NaCl is doped with 10-3mol % of SrCl2, what is the concentration of cation vacancies?
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(ii) 2-Chloro-2-methylbutane
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For the reaction R → P, the concentration of a reactant changes from 0.03 M to 0.02 M in 25 minutes. Calculate the average rate of reaction using units of time both in minutes and seconds.
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