12th Standard Syllabus & Materials
12th Standard
TN 12th Computer Applications மின்னணு தரவு பரிமாற்றம் Sample Question Papers Study Material - QB365 Set A
NEW12th Standard
TN 12th Computer Applications மின் - வணிக பாதுகாப்பு அமைப்புகள் Sample Question Papers Study Material - QB365 Set A
NEW12th Standard
TN 12th Computer Applications மின்னணு செலுத்தல் முறைகள் Sample Question Papers Study Material - QB365 Set A
NEW12th Standard
TN 12th Computer Applications மின் - வணிகம் Sample Question Papers Study Material - QB365 Set A
NEW12th Standard
TN 12th Computer Applications திறந்த மூல கருத்துருக்கள் Sample Question Papers Study Material - QB365 Set A
NEW12th Standard
TN 12th Computer Applications வலையமைப்பு வடமிடல் Sample Question Papers Study Material - QB365 Set A

Published on: 13/05/2022
QB365 provides detailed and simple solution for every Book back Questions in class 12 Chemistry Subject. It will helps to get more idea about question pattern in every book back questions with solution.
latest Book back QuestionsDownload Tamil Nadu 12th Standard Chemistry question papers, model tests, one-mark questions, important questions, and public exam papers in PDF format. Free study materials and answer keys for TN State Board students.
Questions + Answers key
Take MCQ Chemistry Test1.
Write the mechanism of acid catalysed dehydration of ethanol to give ethene.
2.
Hydrolysis of methyl acetate in aqueous solution has been studied by titrating the liberated acetic acid against sodium hydroxide. The concentration of an ester at different temperatures is given below.
| t(min) | 0 | 20 | 40 | 60 | ∝ |
|---|---|---|---|---|---|
| v (ml) | 20.2 | 25.6 | 29.5 | 32.8 | 50.4 |
Show that the reaction is the first order reactions.
3.
Explain the following terms with suitable examples.
(i) Gangue
(ii) slag
4.
5.
Write the structural formula of aspirin.
6.
Give two difference between Hormones and vitamins.
7.
Explain briefly how +2 states becomes more and more stable in the first half of the first row transition elements with increasing atomic number.
8.
What is linkage isomerism? Explain with an example.
9.
How will you prepare chlorine in the laboratory?
10.
Identify A, B, C and D
\(\text { ethanoic acid } \stackrel{\mathrm{SOCl}_{2}}{\longrightarrow} \mathrm{A} \stackrel{\mathrm{Pd} / \mathrm{BaSO}_{4}}{\longrightarrow} \mathrm{B} \stackrel{\mathrm{NaOH}}{\longrightarrow} \mathrm{C} \stackrel {\longrightarrow}{\triangle} \mathrm{D}\)
11.
Arrange the following
i. In increasing order of solubility in water, C6H5 NH2, (C2H5)2NH, C2H5NH2
ii. In increasing order of basic strength
a) aniline, p- toludine and p – nitroaniline
b) C6H5 NH2, C6H5 NHCH3, C6H5NH2, p-Cl-C6- H4-NH2
iii. In decreasing order of basic strength in gas phase
(C2H5)NH2, (C2H5)NH, (C2H5)5N and NH3
iv. In increasing order of boiling point
C6H5OH, (CH3)2NH, C2H5NH2
v. In decreasing order of the pKb values
C2H5NH2, C6H5NHCH3.(C2H5)2 NH and CH3NH2
vi. Increasing order of basic strength
C2H5NH2,C6H5N(CH3)2, (C2H5)2 NH and CH3NH2
vii. In decreasing order of basic strength
12.
The conductivity of a 0.01M solution of a 1 :1 weak electrolyte at 298K is 1.5\(\times\)10-4 S cm−1.
i) molar conductivity of the solution
ii) degree of dissociation and the dissociation constant of the weak electrolyte
Given that
\(\lambda^{0}_{cation}=248.2 \ S\) cm2 mol-1
\(\lambda^{0}_{anlon}=51.8 \ S\) cm2 mol-1
13.
Derive an expression for Ostwald’s dilution law.
14.
Explain AAAA and ABABA and ABCABC type of three dimensional packing with the help of neat diagram.
1.
\({ CH }_{ 3 }-{ CH }_{ 2 }-OH\overset { { H }_{ 2 }{ SO }_{ 4 } }{ \underset { 443k }{ \longrightarrow } } { CH }_{ 2 }={ CH }_{ 2 }+{ H }_{ 2 }O\)
Mechanism
Primary alcohols undergo dehydration by E2 mechanism
2.
\(k=\frac { 2.303 }{ t } \log\frac { \left( { V }_{ \infty }-{ V }_{ 0 } \right) }{ \left( { V }_{ \infty }-{ V }_{ 0 } \right) } \)
\(k=\frac { 2.303 }{ 20 } \log\frac { 50.4-20.2 }{ 50.4-25.6 } \)
\(=0.1151 \log\frac { 30.2 }{ 24.8 } \)
= 0.1151 log 1.2479
= 0.1151 x 0.0959
= 11.03 x10-3 min-1
When t = 40 mts
\(k=\frac { 2.303 }{ 40 } \log\frac { 50.4-20.2 }{ 50.4-25.6 } \)
\(=0.0576\times \log\frac { 30.2 }{ 20.9 } \)
= 9.19 x 10-3 min-1
When t = 60 mts
\(k=\frac { 2.303 }{ 60 } \log\frac { 50.4-20.2 }{ 50.4-25.6 } \)
\(=0.03838\times \log\frac { 30.2 }{ 17.6 } \)
= 0.03838 x 0.2343
= 8.99 x 10-3 min-1
The constant values of K show that the reaction is of first order.
3.
(i) Gangue: The ores are associated with nonmetallic impurities, rocky materials and siliceous matter which are collectively known as gangue.
Eg: SiO2 is the gangue present in the iron ore (Fe2O3)
(ii) Slag: In the smelting process, a flux combines with Silica gangue forming slag.
CaO(s) + SiO2(s) → CaSiO3(s)
Flux + gangue → Slag
4.
5.
Aspirin is o-acetyl salicylic acid
6.
| Hormone | Vitamin |
|---|---|
| Synthesized in animal bodies | Synthesised in plants |
| Produced in ductless (endocrine glands) | Have to be supplied in diet except (Vitamin D) |
| These are not stored in body but are continuously produced | These remain stored in the body to keep away diseases |
| Eg: Androgen, Estrogen, thyroxine etc. | Eg: Vitamin A (Retinol) Vitamin C (Ascorbic acid) |
7.
In 3d series as we move from Ti to Zn, the standard reduction potential \(\left(\mathrm{E}_{\mathrm{M}^{2+} / \mathrm{M}}^{0}\right)\) value is approaching towards less negative value and copper has a positive reduction potential. If the standard electrode potential E0, of a metal is large and negative, the metal is a powerful reducing agent, because it loses electrons easily. Hence +2 states becomes more and more stable in the first half of the first row transition elements.
8.
(i) This is also called as salt isomerism.
(ii) This type of isomers arises when an ambidentate ligand is bonded to the central metal atom/ion through either of its two different donor atoms. In the below mentioned examples, the nitrite ion is bound to the central metal ion Co3+ through a nitrogen atom in one complex and through oxygen atom in other complex.
\(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5}\left(\mathrm{NO}_{2}\right)\right]^{2+}\)
9.
Chlorine is prepared by the action of conc. sulphuric acid on chlorides in presence of manganese dioxide
4NaCl + MnO2 + 4H2SO4 \(\longrightarrow \)Cl2+ MnCl2 +4NaHSO4 + 2H2O
10.
| Compound | Name |
| A | Acetylchloride |
| B | Acetaldehyde |
| C | 3 - Hydroxy butanal |
| D | Crotonaldehyde |
11.
i) In increasing order of solubility in water:
\(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2},\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{2} \mathrm{NH}, \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2} \)
\(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2}>\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}>\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{2} \mathrm{NH}\)
ii) In increasing order of basic strength:
a. Aniline, p - toluidine and p - nitro aniline
p - toluidine > aniline >p - nitro aniline
b. \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}, \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NHCH}_{3}, \mathrm{p}-\mathrm{Cl}-\mathrm{C}_{6} \mathrm{H}_{4}-\mathrm{NH}_{2} \)
\(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NHCH}_{3}>\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}>\mathrm{p}-\mathrm{Cl}-\mathrm{C}_{6} \mathrm{H}_{4}-\mathrm{NH}_{2}\\ 2^{o} \text { amine } \quad \quad \quad \quad e^{\ominus} \text { with drawing (group) }\)
(iii) In decreasing order of basic strength in gas phase:
\(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2},\left(\mathrm{C}_{2} \mathrm{H}_{5}\right) \mathrm{NH},\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{3} \mathrm{~N} \text { and } \mathrm{NH}_{3} \)
\(\mathrm{NH}_{3}<\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2}<\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{2} \mathrm{~N}<\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{3} \mathrm{NH}\\ \quad \quad \quad 1^{0} \text { amine } \quad 2^{0} \text { amine } \quad \quad \quad 3^{0} \text { amine }\)
(iv) In increasing order of boiling point:
\(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{OH},\left(\mathrm{CH}_{3}\right)_{2} \mathrm{NH}, \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2} \)
\(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{NH}>\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2}>\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{OH} \\ 2^{0} \text { amine } \quad \quad1^{0} \text { amine }\)
Generally amines have lower boiling point than alcohol. Due to comparable molecular mass and weaker H-bonds in Amines.
(v) In decreasing order of the pKb values:
\( \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2}, \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NHCH}_{3},\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{2} \mathrm{NH} \text { and } \mathrm{CH}_{3} \mathrm{NH}_{2} \)
\(\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{2} \mathrm{NH}<\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2}<\mathrm{CH}_{3} \mathrm{NH}_{2}<\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NHCH}_{3} \)
\(\quad \quad \quad 2^{0} \text { amine } \quad 1^{0} \text { amine } 1^{0} \text { amine } \quad 2^{0} \text { amine } \)
\(\mathrm{PK}_{b}: \quad 3.00\quad < \quad 3.29 \quad < \quad 3.38 \quad<\quad 9.30\)
pKb ,Due to + 1 effect of C2H5 group. Higher the value of pKb lower is the basicity
(vi) Increasing Order of basic strength:
\(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}, \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{~N}\left(\mathrm{CH}_{3}\right)_{2},\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{2} \mathrm{NH} \text { and } \mathrm{CH}_{3} \mathrm{NH}_{2} \)
\(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}>\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{~N}\left(\mathrm{CH}_{3}\right)_{2}>\mathrm{CH}_{3} \mathrm{NH}_{2}>\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{2} \mathrm{NH} \\ \left(\mathrm{pK}_{6}: 9.38 \quad > \quad \quad 8.92 \quad \quad > \quad 3.38 \quad > \quad \quad 3.00\right)\)
Due to + 1 effect of C2H5 group.
In decreasing order of basic strength:
12.
i) Molar conductivity
Given : C = 0.01 M;
\(\kappa=1.5 \times 10^{-4} \mathrm{~S} \mathrm{~cm}^{-1} \)
\(=1.5 \times 10^{-2} \mathrm{~S} \mathrm{~m}^{-1} \)
\(\lambda_{\text {cation }}^{0}=248.2 \mathrm{~S} \mathrm{~cm}^{2} \mathrm{~mol}^{-1} \)
\(\lambda_{\text {anion }}^{0}=51.8 \mathrm{~S} \mathrm{~cm}^{2} \mathrm{~mol}^{-1} \)
\(\Lambda_{m}^{0}=\frac{\kappa \times 10^{-3}}{C} \mathrm{~S} \mathrm{~m}^{2} \mathrm{~mol}^{-1} \)
\(=\frac{1.5 \times 10^{-2} \times 10^{-3}}{0.01} \)
\(=1.5 \times 10^{-3} \mathrm{~S} \mathrm{~m}^{2} \mathrm{~mol}^{-1}\)
ii) \(\alpha=\frac{\Lambda_{m}}{\Lambda_{m}^{0}}\)
\(\Lambda_{\mathrm{m}}^{0}=\lambda_{\text {cation }}^{0}+\lambda_{\text {anion }}^{0} \)
\(=(248.2+51.8) \mathrm{S} \mathrm{cm}^{2} \mathrm{~mol}^{-1} \)
\(=300 \mathrm{~S} \mathrm{~cm}^{2} \mathrm{~mol}^{-1}\)
\(=300 \times 10^{-4} \mathrm{Sm}^{2} \mathrm{~mol}^{-1} \)
\(\alpha =\frac{1.5 \times 10^{-3}}{300 \times 10^{-4}}=0.05\)
iii) \(\mathrm{K}_{\mathrm{a}} =\frac{\alpha^{2} \mathrm{C}}{1-\alpha} \)
\(\mathrm{K}_{\mathrm{a}} =\frac{(0.05)^{2} \times(0.01)}{1-0.05}=2.6 \times 10^{-5} \)
(or)
\(\mathrm{K}_{\mathrm{a}} =\alpha^{2} \mathrm{C} \)
\(=(0.05)^{2} \times(0.01) \)
\(\mathrm{K}_{\mathrm{a}} =2.5 \times 10^{-5}\)
13.
(i) Ostwald's dilution law relates the dissociation constant of the weak acid (Ka) with its degree of dissociation (α) and the concentration (c).
where \(\alpha=\frac{\text { Number of moles dissociated }}{\text { Total number of moles }}\)
(ii) The dissociation of acetic acid can be represented as
\(\mathrm{CH}_{3} \mathrm{COOH} \rightleftharpoons \mathrm{H}^{+}+\mathrm{CH}_{3} \mathrm{COO}^{-}\)
The dissociation constant of acetic acid is,
\({ K }_{ a }=\frac { \left[ { H }^{ + } \right] \left[ { CH }_{ 3 }COO^{ - } \right] }{ \left[ { CH }_{ 3 }COOH \right] } \) ........(1)
| CH3COOH | H+ | CH3COO- | |
| Initial number of moles | 1 | - | - |
| Degree of dissociation of CH3COOH | α | - | - |
| Number of moles at equilibrium | 1-α | α | α |
| Equilibrium concentration | (1-α)C | αC | αC |
Substituting the equilibrium concentration in equation (1)
\({ K }_{ a }=\cfrac { \left( \alpha C \right) \left( \alpha C \right) }{ \left( 1-\alpha \right) C } \)
\({ K }_{ a }=\cfrac { { \alpha }^{ 2 }C }{ 1-\alpha } \) .......(2)
(iii) We know that weak acid dissociates only to a very small extent compared to one, a is so small and hence in the denominator (1 - α) ⋍1. The above expression (2) now becomes,
ka =a2C \(\Rightarrow { \alpha }^{ 2 }=\cfrac { { k }_{ a } }{ C } \) ; \(\alpha =\sqrt { \cfrac { { K }_{ a } }{ C } } \)
(iv) When dilution increases, the degree of dissociation of weak electrolyte also increases. This is called Ostwald's dilution law
Also \(;\left[\mathrm{H}^{+}\right]=\alpha \mathrm{C}\) and \(\left[\mathrm{H}^{+}\right]=\left(\sqrt{\frac{\mathrm{K}_{\mathrm{a}}}{\mathrm{C}}}\right) \mathrm{C}=\sqrt{\frac{\mathrm{K}_{\mathrm{a}} \mathrm{C}^{2}}{\mathrm{C}}}=\sqrt{\mathrm{K}_{\mathrm{a}} \cdot \mathrm{C}}\)
Similarly for a weak base
\(\begin{aligned} & \mathrm{K}_{\mathrm{b}}=\alpha^2 \mathrm{C} ; \quad \therefore \alpha=\sqrt{\frac{\mathrm{k}_{\mathrm{b}}}{\mathrm{C}}}, \\ \end{aligned}\)
\(\begin{aligned} & {\left[\mathrm{OH}^{-}\right] \alpha \mathrm{C}=\sqrt{\frac{\mathrm{K}_{\mathrm{b}}}{\mathrm{C}}} \times \mathrm{C}=\sqrt{\frac{\mathrm{K}_{\mathrm{b}} \mathrm{C}^2}{\mathrm{C}}}=\sqrt{\mathrm{K}_{\mathrm{b}} \mathrm{C}}} \end{aligned}\)
14.
AAAA type of three dimensional packing:
1. This is simple cubic arrangement.
2. Three dimensional packing arrangement can be obtained by repeating the AAAA type two dimensional arrangements in three dimensions.
3. Spheres in one layer sitting directly on the top of in the previous layer so that all layers are identical.
4. All spheres of different layers of crystal are perfectly aligned horizontally and also vertically.
5. In simple cubic packing, each sphere is in contact with 6 neighbouring spheres
6. Four in its own layer, one above and one below and hence the coordination number of the sphere in simple cubic arrangement is 6.
ABABA type of three dimensional packing:
(i) This is body centered cubic arrangement.
(ii) The spheres in the first layer are slightly separated and the second layer is formed by arranging the spheres in the depressions between the spheres in layer A.
(iii) The third layer is a repeat of the first.
(iv) This pattern ABABAB is repeated throughout the crystal.
(v) Each sphere has a coordination number of 8, four neighbors in the layer above and four in the layer below.
ABCABC type of three dimensional packing:
(i) This is face centered cubic arrangement.
(ii) In this arrangement (FCC) second layer spheres are arranged at the dips of first layer. Third layer spheres are arranged in a manner such that it cover the octahedral void.
(iii) Then no longer third layer is similar to first or second layer.
(iv) Third layer gives different arrangement. Fourth layer spheres are similar to first layer.
(v) If the first, second and third layer are represented as A, B, C then this type of packing gives the arrangement of layers as ABCABC.. and the sequence is repeated.
12th Standard Syllabus & Materials
12th Standard
TN 12th Computer Applications களப்பெயர் முறைமை (DNS) Sample Question Papers Study Material - QB365 Set A
NEW12th Standard
TN 12th Computer Applications வலையமைப்பு எடுத்துக்காட்டுகள் மற்றும் நெறிமுறைகள் Sample Question Papers Study Material - QB365 Set A
NEW12th Standard
TN 12th Computer Applications கணினி வலையமைப்பு ஓர் அறிமுகம் Sample Question Papers Study Material - QB365 Set A
NEW12th Standard
TN 12th Computer Applications PHP-உடன் MySQL-ஐ இணைத்தல் Sample Question Papers Study Material - QB365 Set A
Tamilnadu Stateboard 12th Standard Subjects

Maths

Chemistry

Physics

Biology

Computer Science

Business Maths and Statistics

Economics

Commerce

Accountancy

History

Computer Applications

Biology

Computer Technology

Computer Applications

Computer Science

Business Maths and Statistics

Commerce

Economics

Maths

Chemistry

Physics

Computer Technology

History

Accountancy

Tamil

English

French
Tamilnadu Stateboard Standards