Model Paper-1
Chemistry
CBSE (2001)
Model Paper 2 >>
Q 1.Arrange the Electron (e), Proton (p), Neutron
& Alpha particles (a) with increasing order of their value of e/m (charge/mass)? (1 mark)
Ans. - Neutron, Alpha (a), Proton (p), Electron (e)
Q 2. How does Cl from Cl- ion differ from each other? (1mark)
Ans. In numbers of electron.
Explanation: - Cl + e- Cl-
Q 3.Why is NaCl electrovalent while CCl4 a covalent compound? (1mark)
Ans. Electrovalent bond is formed by the tr
Ansfer of electron from one atom (metal) to another atom (non-metal). Since in NaCl bond is formed by tr
Ansfer of electron from Na to Cl, that's why it has electrovalent bond.
Covalent bond is formed by the sharing of electrons between two or more atoms (non- metals). Since CCl4 is formed by the sharing of electron between carbon & chlorine, that's why CCl4 has a covalent bond.
Q 4.What is diagonal relationship? (1 mark)
Ans. The first element of a group often shows resemblance to the second element of the neighbouring group on the right. This type of relationship is called diagonal relationship. Eg. Lithium and Magnesium.
Q 5.What do you understand by the term " Polymerisation"? (1mark)
Ans. It is a union of two or more molecules of same type to form a new big molecule without any elimination. The molecules are called "Polymers" and this phenomenon is called "Polymerisation".
Illustration: - NH4Cl+Cu2Cl2(as catalyst)
·
Q 6. Write Van der Waal equation? (1mark)
Inter molecular Force
Q 7.Write the name of the atomic reactor in which graphite is used as moderator ? (1mark)
Ans. "Atomic pile"
Q 8.Calculate the number of electrons present in 1.6 gram of CH4? (1mark)
Ans: - 1.6 gm of CH4 = 1.6 /16 mole of CH4 = 10-1 mole of methane
= 6.023 X 1022 molecules of methane = 6.023 X 1022 X 10 electrons = 6.023 X 1023 electrons.
(Here 1 molecules of methane contain one carbon atom & 4 H-atoms consisting of 6+4=10 electrons)
Q 9.What will be total number of orbital in 4th orbit? (1mark)
Ans. (16)
Total No. of orbitals = 16
Q 10.Write the structural formula of "Gamexine"? (1mark)
Ans. The trade name of benzene hexachloride is gammexine. Its structural formula is :
Q 11. Define: -
(i) Aufbau principle
(ii) Heisenberg uncertainty principle.(2 marks )
Ans.(i)
· Aufbau principle: -
Aufbau is a German word, which me
Ans, " to build". Hence, Aufbau principle gives the principles building of atomic structure of elements with electrons.
According to this principle: -
"Electrons are filled in atomic orbital in order of their increasing energy ".
(ii) Uncertainty principles: -
· Given by: - Werner Heisenberg (1927).
· Principles: - It is impossible to measure the position & momentum of a sub-atomic particle in an atom accurately. If p be the error in measuring momentum & x be the error in measuring position of a subatomic particles of an atom then according to Hisenberg's uncertainty principles,
The uncertainty in measuring position & momentum of subatomic particles occurs because light or electron beam has a finite & constant velocity & its velocity can not be made equal to infinity.
Q 12 The radiator of a vehicle holds 10 L of water? If the vehicles is to be used in Srinager where the lowest temperature is -10.0ºC (263.15k), calculate the amount of ethylene glycol (molar mass = 62.1g mol-1 ) which should be added to the water? (2 marks)
Ans. Here kf for water = 1.86 K kg mol-1 .
Molality (m) of a solution which freezes at 263.15 K .
m= T / kf = 10.0k
1.86 K Kg mol-1 = 5.4 mol Kg-1k kg mol-1
Since 5.4 moles of ethylene glycol is needed for 1 Kg of water
Therefore, 54 moles will be needed for 10Kg (i.e. mass of 10L)
=54.0X 62.1gm =335 X 101 of ethylene glycol.
Q 13.Define: -
(i) Osmosis
(ii) Osmotic pressure (2 marks)
Ans.
(i) If a solution is separated from the solvent by a semipermeable membrane, which blocks the solute molecule but allows the passage of solvent molecules from the solvent side to the solution side than from solution side to the solvent side. This phenomenon which results in a net flow of solvent to the solution is called Osmosis.
(ii) The passage of solvent through the membrane can be stopped if adequate pressure is applied on the solution side. This is known as Osmotic pressure.
Q 14. Write IUPAC names of the following compounds: -
(i) CH3-CH2-O-CH2-CH-CH3
(ii) CH3-CH2-CH2-CO-CH3(2 marks)
Ans.
(i) 2,ethyl,propyl ether or Ethoxypropane
(ii) 1,Methyl, 2 propyl ketone or Pentanone.
Q 15.Starting from carbon to hydrogen how would you synthesis the following compounds?
(i) Benzene
(ii) Formic acid.(2 marks)
Ans. ..........2500ºC ..................polymerisation
Rate = K [Reactant]n , If concentration of reactant =a
& Rate = r1
and When the concentration of reactant is = 4a, rate =2r1
r1 =K[a]n ----------------->(1)
and, 2r1 =k[4a]n------------------->(2)
Dividing (1) by (2)
1 /2 = [1 /4] Therefore , n= 1 /2 = order of reaction is 0.5
Q 17.What happens when: - (2 marks)
Ans.17
Q 18. Write the chemical name of following structure: - (2 marks)
(ii)
Ans.
(i) DDT ( Dichlor diphenyl trichloro ethane)
(ii) 1,3,5 Trimethyl benzene (Mesitylene)
Q 19.Explain: -
a) Cannizzaro's reaction
b) Kolbe's electrolysis
c)Williamson's Synthesis.(2 marks)
Ans.(a) Cannizzaro's reaction: -Aldehydes which does not contain any a-hydrogen atom (HCHO, C6H5CHO) undergo self-oxidation and reduction reaction on treatment with concentrated alkali. In this one molecule of aldehyde is reduced to alcohol and other oxidised to the acid. Thus a mixture containing an alcohol and a salt of carboxylic acid is formed. This is Cannizzaro's reaction.
(b) Kolbe's reaction; -When an alkali metal salt of carboxylic acid is electrolysed, then decarboxylation occurs at the anode. This is known as Kolbe's electrolysis.
c)Willimson's synthesis: - When an alkyl halide is treated with sodium alkoxide prepared from sodium and alcohol, a nucleophilic replacement of halogen atom by alkoxide group takes place. This is known as Williamson's Synthesis.
2R'-OH + 2Na 2R'-O-Na+ + H2
R-X + R'O-Na+ R-O-R' + NaX
This reaction is used for preparation of both symmetrical and unsymmetrical ethers.
Q 20) What happens when: - (2 marks)
a) A solution of sodium acetate is electrolysed.
b) Ethyl alcohol is heated with conc. H2SO4.
c) Acetaldehyde is warmed with NaOH.(mark-2)
Q 21) What is an antibiotic? Give the name of the first antibiotic.
(2 marks)
Ans - "Antibiotic is defined as a chemical substance produced by micro-organisms that can inhibit the growth or even destroy other micro-organism".
Penicillin is the 1st known antibiotic discovered by Alexander Fleming.
Q 22) What happen when: -
a) ZnSO4 reacts with NaOH solution
b) ZnSO4 reacts with NH4OH solution
c) Mg(NO3)2 reacts with NH4OH solution.(2 marks)
Ans.
a) ZnSO4 +2 NaOH Na2SO4 + Zn(OH)2
b)ZnSO4 + 2NH4OH Zn(OH)2 + (NH4)2SO4
c) Mg (NO3)2 + 2NH4OH Mg(OH)2 + 2 NH4NO3
Q 23 )A potassium salt of ternary acid of Molybdenum (at. Mass= 96) has the formula K2MoOn. When an acidified solution of K2MoOn is electrolysed between Pt electrodes, O2 gas liberates corresponding to a volume of 0.121 at STP and 0.3454 gm of Mo is deposited. Find the formula of salt. (3 marks)
Ans. No. of Faraday passed = No. of gm eq. Of O2 = gm eq. Of Mo
= 4F = 1 mole of O2
= gm eq. Of O2 = 4 X 0.121 / 22.4 = 0.026
= gm eq. Of Mo = 0.026
g /m= gm eq. Of Mo
= 0.0215=0.3454 / 96 /x
= x =6
Mox+ + 6e Mo
= Oxidation state of Mo = 6
In K2MoOn, we have 2(+1) + 6 + n(-2) =0
= n=4
= molecular formula is K2MoO4
Q 24) How you will distinguish between: -
(i) Acetaldehyde & Propanone
(ii) Formic acid & Acetic acid (2 marks)
Ans.
Acetaldehyde Propanone
1.Acetaldehyde on reduction gives primary alcohol
2. Acetaldehyde on oxidation gives acid, has same Carbon atom.
1. While propanone on reduction gives
Secondary alcohol.
2. It gives acid, which has less no of . carbon
Formic acid Acetic acid
1. Reacts with Tollen's reagent to form silver mirror
2.Formic acids reacts with chlorine to form CO2 & HClHCOOH + Cl2 CO2 + HCl 1. No reaction
2. it gives Chloroacetate acid
CH3COOH + Cl2 CH2ClCOOH
Q 25) What is a fertilizer? Name three important fertilizers. (2 marks)
Ans. Plants needs several elements for their growth. The three most elements for the plants are Nitrogen (for rapid growth & good protein contents), phosphorus (for root growth) & potassium ( for flowering & strength of stalks) .Compound of nitrogen, phosphorus & Potassium, which are put into soil to increase the agriculture production are called Chemical fertilizer .Three important fertilizer are Urea, superphosphates of lime & Calcium superphosphate nitrate.
Q 26)Write down the structural formula of glucose & Fructose & indicate the functional group?(2 marks)
Ans.
Q 27)Complete the following reaction: - (2 marks)
4Be9 + 2He4 6C + n
11Na23 + 1H2 Mg23 + 0n
3Li7 + 1H2 8Li + H1
Ans.
4Be9 + 2He4 6C12 + 0n1
11Na23 + 1H2 12Mg24 + 0n1
3Li7 + 1H2 8Li3 + 1H1
Q 25)What will be the sequence of bases on DNA molecules synthesised on the following strand of chromose? ATTCCGGA (2 marks)
Ans. The sequence is as follows:
TAAGGCCT
Q 26)Mention the geometrical shapes attained by the following types of hybrid orbital: a) SP3 b) dsp3 c) d2sp3 (3 marks)
Ans. a) Tetrahedron b) Triangularbipyramid c)Octahedron
Q 27)Illustrate with an example each of the following :
a) Geometrical isomerism
b) Optical isomerism (3 marks)
Ans.
a) Geometrical isomerism : - This type of isomerism is only due to different geometrical arrangement of atom or group in space. Compound having general formula.
.................................ABC=CAB
Cis form Tr
Ans form (one in which gr. of same type are on same side (one in which gr. of different types is called cis-isomers) are on different sides is called tr
Ans-isomers)
b) Optical isomerism: -This type of isomerism is only due to presence of at least one asymmetric carbon atom & the same compound behaves differently towards polarised light. The different forms are known as Optical isomerism. These are dextro or levo rotatory
(Hints: -A carbon atom having four different atoms or groups is called Asymmetric carbon atom, e.g. cabxy)
Q 28)Arrange the following in the decreasing order of property indicated:
(i) F2, Cl2, Br2, I2 Bond energy
(ii) HF, HCl, HBr, HI acid strength ( in water)
(iii) M-F, M-Cl, M-Br, M-I ionic character of the bond (mark-3)
Ans: -
(i) F2> Cl2> Br2> I2
As the size of the halide ion increases the energy of dissociation decrease.
(ii) HF> HCl> HBr> HI
Fluoric acid is stronger than hydrochlic acid.
(iii) M-F>M-Cl> M-Br> M-I
Q 29)What is Buna-S? How it is synthesised? (2 marks)
Ans. It is a synthetic rubber, obtained by polymerisation of butadiene & styrene. Bunna-S rubber:-
CH2=CH-CH=CH + C6H5-CH-CH2------------> (-CH2=CH-CH=CH2-CH-CH2-)n
l................................................................................................|
................................................................................................C6H5
Butadiene Styrene ...........................................................Bunna-S
Q 30)Write nuclear equation for the following tr
Ansformations:
a) 233Th90 undergoes ß-decay
b) 218At85 undergoes a-decay (3 marks)
Q 31) If the radioactive element 235X92 emits one alpha particle & two beta particles, then:
i) What will the atomic number & atomic mass of daughter elements "y".
ii) What will be the relation between parent element X & daughter elements Y.(mark-3)
Ans.
Q 32)Write down all the quantum number of the 8th electron of Cl -atom? (3 marks)
Ans.
Cl (17) 1s2,2s2, 2p6,3s2,3p5
The arrangement of electron in Cl-atom in 2p orbital is shown below according to Hund's rule
Therefore, 8th electrons of Cl-atom are 2px orbital & its spin in the anticlockwise direction. It's four quantum no. are:
n=2, l=1, m= -1 & s= -1 /2
Q 33) Explain: -
i) Bronsted-Lowery acid-base concept
ii) Arrehenius theory (3 marks)
Ans.
· i) Bronsted-Lowery Theory: -
According to him,
" an acid is a proton donor while base is a proton acceptor"
HCl + H2O � H3O+ (aq) + Cl- (aq)
ii)
· Bronsted-Lowery Theory: -
According to him,
" an acid is a proton donor while base is a proton acceptor"
HCl + H2O � H3O+ (aq) + Cl- (aq)
· ii) Bronsted-Lowery Theory: -
According to him,
" an acid is a proton donor while base is a proton acceptor"
HCl + H2O � H3O+ (aq) + Cl- (aq)
ii)
According to Arrehenius,
Acid: -
" An acid is a compound which contains replaceable hydrogen atom or atoms, a part or whole of which can be replaced by me
Ans of a metal or a positive radical".
· Base: -
According to Arrehenius,
"A base is a compound which contain replaceable oxide or hydroxide".
# Complete replacement by metals.
HCl + NaOH NaCl + H2O
HNO3 + NaOH NaNO3 + H2O
H2SO4 + 2NaOH Na2SO4 + 2H2O
# Complete replacement by a group of elements called radical.
HCl + NH4OH NH4Cl + H2O
HNO3 + NH4OH NH4NO3 + H2O
# Partial replacement by metal or ammonium group: -
H2SO4 +NaOH NaHSO4 + H2O
H2SO4 + NH4OH NH4HSO4 + H2O
http://www.yuvajobs.com/education/model/chem.asp
Chemistry
CBSE (2001)
Model Paper 2 >>
Q 1.Arrange the Electron (e), Proton (p), Neutron
& Alpha particles (a) with increasing order of their value of e/m (charge/mass)? (1 mark)Ans. - Neutron
, Alpha (a), Proton (p), Electron (e)Q 2. How does Cl from Cl- ion differ from each other? (1mark)
Ans. In numbers of electron.
Explanation: - Cl + e- Cl-
Q 3.Why is NaCl electrovalent while CCl4 a covalent compound? (1mark)
Ans. Electrovalent bond is formed by the tr
Ansfer of electron from one atom (metal) to another atom (non-metal). Since in NaCl bond is formed by tr
Ansfer of electron from Na to Cl, that's why it has electrovalent bond.
Covalent bond is formed by the sharing of electrons between two or more atoms (non- metals). Since CCl4 is formed by the sharing of electron between carbon & chlorine, that's why CCl4 has a covalent bond.
Q 4.What is diagonal relationship? (1 mark)
Ans. The first element of a group often shows resemblance to the second element of the neighbouring group on the right. This type of relationship is called diagonal relationship. Eg. Lithium and Magnesium.
Q 5.What do you understand by the term " Polymerisation"? (1mark)
Ans. It is a union of two or more molecules of same type to form a new big molecule without any elimination. The molecules are called "Polymers" and this phenomenon is called "Polymerisation".
Illustration: - NH4Cl+Cu2Cl2(as catalyst)
·
Q 6. Write Van der Waal equation? (1mark)
Inter molecular Force
Q 7.Write the name of the atomic reactor in which graphite is used as moderator ? (1mark)
Ans. "Atomic pile"
Q 8.Calculate the number of electrons present in 1.6 gram of CH4? (1mark)
Ans: - 1.6 gm of CH4 = 1.6 /16 mole of CH4 = 10-1 mole of methane
= 6.023 X 1022 molecules of methane = 6.023 X 1022 X 10 electrons = 6.023 X 1023 electrons.
(Here 1 molecules of methane contain one carbon atom & 4 H-atoms consisting of 6+4=10 electrons)
Q 9.What will be total number of orbital in 4th orbit? (1mark)
Ans. (16)
Total No. of orbitals = 16
Q 10.Write the structural formula of "Gamexine"? (1mark)
Ans. The trade name of benzene hexachloride is gammexine. Its structural formula is :
Q 11. Define: -
(i) Aufbau principle
(ii) Heisenberg uncertainty principle.(2 marks )
Ans.(i)
· Aufbau principle: -
Aufbau is a German word, which me
Ans, " to build". Hence, Aufbau principle gives the principles building of atomic structure of elements with electrons.
According to this principle: -
"Electrons are filled in atomic orbital in order of their increasing energy ".
(ii) Uncertainty principles: -
· Given by: - Werner Heisenberg (1927).
· Principles: - It is impossible to measure the position & momentum of a sub-atomic particle in an atom accurately. If p be the error in measuring momentum & x be the error in measuring position of a subatomic particles of an atom then according to Hisenberg's uncertainty principles,
The uncertainty in measuring position & momentum of subatomic particles occurs because light or electron beam has a finite & constant velocity & its velocity can not be made equal to infinity.
Q 12 The radiator of a vehicle holds 10 L of water? If the vehicles is to be used in Srinager where the lowest temperature is -10.0ºC (263.15k), calculate the amount of ethylene glycol (molar mass = 62.1g mol-1 ) which should be added to the water? (2 marks)
Ans. Here kf for water = 1.86 K kg mol-1 .
Molality (m) of a solution which freezes at 263.15 K .
m= T / kf = 10.0k
1.86 K Kg mol-1 = 5.4 mol Kg-1k kg mol-1
Since 5.4 moles of ethylene glycol is needed for 1 Kg of water
Therefore, 54 moles will be needed for 10Kg (i.e. mass of 10L)
=54.0X 62.1gm =335 X 101 of ethylene glycol.
Q 13.Define: -
(i) Osmosis
(ii) Osmotic pressure (2 marks)
Ans.
(i) If a solution is separated from the solvent by a semipermeable membrane, which blocks the solute molecule but allows the passage of solvent molecules from the solvent side to the solution side than from solution side to the solvent side. This phenomenon which results in a net flow of solvent to the solution is called Osmosis.
(ii) The passage of solvent through the membrane can be stopped if adequate pressure is applied on the solution side. This is known as Osmotic pressure.
Q 14. Write IUPAC names of the following compounds: -
(i) CH3-CH2-O-CH2-CH-CH3
(ii) CH3-CH2-CH2-CO-CH3(2 marks)
Ans.
(i) 2,ethyl,propyl ether or Ethoxypropane
(ii) 1,Methyl, 2 propyl ketone or Pentanone.
Q 15.Starting from carbon to hydrogen how would you synthesis the following compounds?
(i) Benzene
(ii) Formic acid.(2 marks)
Ans. ..........2500ºC ..................polymerisation
Rate = K [Reactant]n , If concentration of reactant =a
& Rate = r1
and When the concentration of reactant is = 4a, rate =2r1
r1 =K[a]n ----------------->(1)
and, 2r1 =k[4a]n------------------->(2)
Dividing (1) by (2)
1 /2 = [1 /4] Therefore , n= 1 /2 = order of reaction is 0.5
Q 17.What happens when: - (2 marks)
Ans.17
Q 18. Write the chemical name of following structure: - (2 marks)
(ii)
Ans.
(i) DDT ( Dichlor diphenyl trichloro ethane)
(ii) 1,3,5 Trimethyl benzene (Mesitylene)
Q 19.Explain: -
a) Cannizzaro's reaction
b) Kolbe's electrolysis
c)Williamson's Synthesis.(2 marks)
Ans.(a) Cannizzaro's reaction: -Aldehydes which does not contain any a-hydrogen atom (HCHO, C6H5CHO) undergo self-oxidation and reduction reaction on treatment with concentrated alkali. In this one molecule of aldehyde is reduced to alcohol and other oxidised to the acid. Thus a mixture containing an alcohol and a salt of carboxylic acid is formed. This is Cannizzaro's reaction.
(b) Kolbe's reaction; -When an alkali metal salt of carboxylic acid is electrolysed, then decarboxylation occurs at the anode. This is known as Kolbe's electrolysis.
c)Willimson's synthesis: - When an alkyl halide is treated with sodium alkoxide prepared from sodium and alcohol, a nucleophilic replacement of halogen atom by alkoxide group takes place. This is known as Williamson's Synthesis.
2R'-OH + 2Na 2R'-O-Na+ + H2
R-X + R'O-Na+ R-O-R' + NaX
This reaction is used for preparation of both symmetrical and unsymmetrical ethers.
Q 20) What happens when: - (2 marks)
a) A solution of sodium acetate is electrolysed.
b) Ethyl alcohol is heated with conc. H2SO4.
c) Acetaldehyde is warmed with NaOH.(mark-2)
Q 21) What is an antibiotic? Give the name of the first antibiotic.
(2 marks)
Ans - "Antibiotic is defined as a chemical substance produced by micro-organisms that can inhibit the growth or even destroy other micro-organism".
Penicillin is the 1st known antibiotic discovered by Alexander Fleming.
Q 22) What happen when: -
a) ZnSO4 reacts with NaOH solution
b) ZnSO4 reacts with NH4OH solution
c) Mg(NO3)2 reacts with NH4OH solution.(2 marks)
Ans.
a) ZnSO4 +2 NaOH Na2SO4 + Zn(OH)2
b)ZnSO4 + 2NH4OH Zn(OH)2 + (NH4)2SO4
c) Mg (NO3)2 + 2NH4OH Mg(OH)2 + 2 NH4NO3
Q 23 )A potassium salt of ternary acid of Molybdenum (at. Mass= 96) has the formula K2MoOn. When an acidified solution of K2MoOn is electrolysed between Pt electrodes, O2 gas liberates corresponding to a volume of 0.121 at STP and 0.3454 gm of Mo is deposited. Find the formula of salt. (3 marks)
Ans. No. of Faraday passed = No. of gm eq. Of O2 = gm eq. Of Mo
= 4F = 1 mole of O2
= gm eq. Of O2 = 4 X 0.121 / 22.4 = 0.026
= gm eq. Of Mo = 0.026
g /m= gm eq. Of Mo
= 0.0215=0.3454 / 96 /x
= x =6
Mox+ + 6e Mo
= Oxidation state of Mo = 6
In K2MoOn, we have 2(+1) + 6 + n(-2) =0
= n=4
= molecular formula is K2MoO4
Q 24) How you will distinguish between: -
(i) Acetaldehyde & Propanone
(ii) Formic acid & Acetic acid (2 marks)
Ans.
Acetaldehyde Propanone
1.Acetaldehyde on reduction gives primary alcohol
2. Acetaldehyde on oxidation gives acid, has same Carbon atom.
1. While propanone on reduction gives
Secondary alcohol.
2. It gives acid, which has less no of . carbon
Formic acid Acetic acid
1. Reacts with Tollen's reagent to form silver mirror
2.Formic acids reacts with chlorine to form CO2 & HClHCOOH + Cl2 CO2 + HCl 1. No reaction
2. it gives Chloroacetate acid
CH3COOH + Cl2 CH2ClCOOH
Q 25) What is a fertilizer? Name three important fertilizers. (2 marks)
Ans. Plants needs several elements for their growth. The three most elements for the plants are Nitrogen (for rapid growth & good protein contents), phosphorus (for root growth) & potassium ( for flowering & strength of stalks) .Compound of nitrogen, phosphorus & Potassium, which are put into soil to increase the agriculture production are called Chemical fertilizer .Three important fertilizer are Urea, superphosphates of lime & Calcium superphosphate nitrate.
Q 26)Write down the structural formula of glucose & Fructose & indicate the functional group?(2 marks)
Ans.
Q 27)Complete the following reaction: - (2 marks)
4Be9 + 2He4 6C + n
11Na23 + 1H2 Mg23 + 0n
3Li7 + 1H2 8Li + H1
Ans.
4Be9 + 2He4 6C12 + 0n1
11Na23 + 1H2 12Mg24 + 0n1
3Li7 + 1H2 8Li3 + 1H1
Q 25)What will be the sequence of bases on DNA molecules synthesised on the following strand of chromose? ATTCCGGA (2 marks)
Ans. The sequence is as follows:
TAAGGCCT
Q 26)Mention the geometrical shapes attained by the following types of hybrid orbital: a) SP3 b) dsp3 c) d2sp3 (3 marks)
Ans. a) Tetrahedron b) Triangularbipyramid c)Octahedron
Q 27)Illustrate with an example each of the following :
a) Geometrical isomerism
b) Optical isomerism (3 marks)
Ans.
a) Geometrical isomerism : - This type of isomerism is only due to different geometrical arrangement of atom or group in space. Compound having general formula.
.................................ABC=CAB
Cis form Tr
Ans form (one in which gr. of same type are on same side (one in which gr. of different types is called cis-isomers) are on different sides is called tr
Ans-isomers)
b) Optical isomerism: -This type of isomerism is only due to presence of at least one asymmetric carbon atom & the same compound behaves differently towards polarised light. The different forms are known as Optical isomerism. These are dextro or levo rotatory
(Hints: -A carbon atom having four different atoms or groups is called Asymmetric carbon atom, e.g. cabxy)
Q 28)Arrange the following in the decreasing order of property indicated:
(i) F2, Cl2, Br2, I2 Bond energy
(ii) HF, HCl, HBr, HI acid strength ( in water)
(iii) M-F, M-Cl, M-Br, M-I ionic character of the bond (mark-3)
Ans: -
(i) F2> Cl2> Br2> I2
As the size of the halide ion increases the energy of dissociation decrease.
(ii) HF> HCl> HBr> HI
Fluoric acid is stronger than hydrochlic acid.
(iii) M-F>M-Cl> M-Br> M-I
Q 29)What is Buna-S? How it is synthesised? (2 marks)
Ans. It is a synthetic rubber, obtained by polymerisation of butadiene & styrene. Bunna-S rubber:-
CH2=CH-CH=CH + C6H5-CH-CH2------------> (-CH2=CH-CH=CH2-CH-CH2-)n
l................................................................................................|
................................................................................................C6H5
Butadiene Styrene ...........................................................Bunna-S
Q 30)Write nuclear equation for the following tr
Ansformations:
a) 233Th90 undergoes ß-decay
b) 218At85 undergoes a-decay (3 marks)
Q 31) If the radioactive element 235X92 emits one alpha particle & two beta particles, then:
i) What will the atomic number & atomic mass of daughter elements "y".
ii) What will be the relation between parent element X & daughter elements Y.(mark-3)
Ans.
Q 32)Write down all the quantum number of the 8th electron of Cl -atom? (3 marks)
Ans.
Cl (17) 1s2,2s2, 2p6,3s2,3p5
The arrangement of electron in Cl-atom in 2p orbital is shown below according to Hund's rule
Therefore, 8th electrons of Cl-atom are 2px orbital & its spin in the anticlockwise direction. It's four quantum no. are:
n=2, l=1, m= -1 & s= -1 /2
Q 33) Explain: -
i) Bronsted-Lowery acid-base concept
ii) Arrehenius theory (3 marks)
Ans.
· i) Bronsted-Lowery Theory: -
According to him,
" an acid is a proton donor while base is a proton acceptor"
HCl + H2O � H3O+ (aq) + Cl- (aq)
ii)
· Bronsted-Lowery Theory: -
According to him,
" an acid is a proton donor while base is a proton acceptor"
HCl + H2O � H3O+ (aq) + Cl- (aq)
· ii) Bronsted-Lowery Theory: -
According to him,
" an acid is a proton donor while base is a proton acceptor"
HCl + H2O � H3O+ (aq) + Cl- (aq)
ii)
According to Arrehenius,
Acid: -
" An acid is a compound which contains replaceable hydrogen atom or atoms, a part or whole of which can be replaced by me
Ans of a metal or a positive radical".
· Base: -
According to Arrehenius,
"A base is a compound which contain replaceable oxide or hydroxide".
# Complete replacement by metals.
HCl + NaOH NaCl + H2O
HNO3 + NaOH NaNO3 + H2O
H2SO4 + 2NaOH Na2SO4 + 2H2O
# Complete replacement by a group of elements called radical.
HCl + NH4OH NH4Cl + H2O
HNO3 + NH4OH NH4NO3 + H2O
# Partial replacement by metal or ammonium group: -
H2SO4 +NaOH NaHSO4 + H2O
H2SO4 + NH4OH NH4HSO4 + H2O
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