Chemistry:2004:CBSE:[All India]:Set-I
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Q1
Define the term 'amorphous' . Marks:1View AnswerAnswer:
The substances whose constituent particles are not arranged in any regular order are called amorphous. -
Q2
What is the sum of the mole fractions of all the components in a three component system ? Marks:1View AnswerAnswer:
The sum of mole fractions of all the components in a three component system is one. -
Q3
What is meant by an elementary reaction? Marks:1View AnswerAnswer:
The step which contributes to overall reaction is called elementary reaction. -
Q4
Draw the structure of 4-methylpent-3-en-2-one. Marks:1View AnswerAnswer:
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Q5
Write the IUPAC name the following:
Marks:1View AnswerAnswer:
N,Ndimethylphenylamineethanoate. -
Q6
Compare the relative stability of the following species and indicate their magnetic (diamagnetic or paramagnetic) properties: 
Marks:2View AnswerAnswer:
Not in 2008 CBSE syllabus -
Q7
How does molar conductivity vary with concentration for (i) weak electrolyte and for (ii) strong electrolyte? Give reasons for these variations. Marks:2View AnswerAnswer:
(i) Molar conductance depends on number of ions furnished by electrolyte which is determined by degree of dissociation. For weak electrolytes molar conductance increases with dilution because degree of dissociation increases with dilution. (ii) For strong electrolytes molar conductance does not increase much with dilution because strong electrolytes are completely dissociated at all concentrations and dilution does not increase the degree of dissociation and number of ions. The slight increase in molar conductance on dilution is due to decrease in inter-ionic attraction on dilution. -
Q8
Give the chemical reactions as an evidence for each of the following observations. (i) Tin (II) is a reducing agent whereas Pb (II) is not.
(ii) Gallium +1 undergoes dispropotionation reaction.Marks:2View AnswerAnswer:
Not in 2008 CBSE syllabus. -
Q9
Identify and indicate the presence of centre of chirality, if any, in the following molecules. How many stereoisomers are possible for those containing chiral centre?
(i) 1, 2-dichloropropane
(ii) 3-bromo-pent-1-eneMarks:2View AnswerAnswer:
(i)
1, 2-dichloropropane:- It has one centre of chirality. 
No. of stereoisomers = 2n
Where n=no. of chiral carbon atoms
So, no. of stereoisomers = 1
(ii) 3-bromo-pent-1-ene:- It has also one centre of chirality.
No. of stereoisomers = 2n
Where n=no. of chiral carbon atoms
So, no. of stereoisomers = 1 -
Q10
What happens when ethanol is heated with concentrated sulphuric acid at 453 K? Explain the mechanism of this reaction. Marks:2View AnswerAnswer:
Mechanism:- Dehydration of an alcohol to alkene in the presence of conc. H2SO4 takes place as follows:- 
