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Roll No.
Series 08789
Code No. 043
Navodaya Vidyalaya Samiti
Chemistry (Theory) Sample Paper - 8
Class-12th
Time allowed: 3 Hours
Maximum Marks: 70
General Instructions:
Q1
(i)
All questions are compulsory.
(ii)
Marks for each question are indicated against it.
(iii)
Questions number 1 to 8 are very short answer questions and carry 1 marks each.
(iv)
Questions number 9 to 18 are short answer questions and carry 2 marks each.
(v)
Questions number 19 to 27 are also short answer questions and carry 3 marks each.
(vi)
Questions number 28 to 30 are long answer questions and carry 5 marks each.
(vii)
Use Log Tables, if necessary. Use of calculators is not allowed.
In the Coagulation of negative sol arrange the following ions increasing order of 1
flocculating power Al3+, Ba2+, Na+
Q2
Give IUPAC name of linkage isomer of [CO(NH3)5(NO2)]Cl2
1
Q3
How do you account for the miscibility of ethanol with water?
1
Q4
Give IUPAC name of the compound
1
O
CH3
Q5
Name the monomer of Bakelite.
1
Q6
Give one example of an artificial sweetener used by the diabetic patients.
1
Q7
Direct nitration of aniline is not carried out. Explain why?
1
Q8
In proteins the -aminoacids are connected by which bonds.
1
-1-
Q9
Examine the illustration of a portion of the defective crystal given below and
answer the following questions.
-+-+-+-+-+-+-+-+
+-+-+-+-+-+e+-+-+-+-+-+-+-+-+-+
Q10
(a) What do you call the anionic sites occupied by unpaired electron.
1
(b) Name one ionic compound, which shows this type of defect.
1
Analysis shows that a metal oxide has the empirical formula M0.96 O1.00. 2
Calculate the percentage of M2+ and M3+ ions in this crystal.
OR
A compound is formed by two elements X and Y. Atoms of the elements Y (as 2
anions) make ccp and those of element X (as cations) occupy all the octahedral
voids. What is the formula of the compound and co-ordination number of
cations.
Q11
1.00g of a non-electrolyte solute dissolved in 50 g of benzene lowered the 2
freezing point of benzene by 0.40oC. the freezing point depression constant of
benzene is
5.12 K kg mol-1. Find the molar mass of the solute.
Q12
Why rusting of iron is an electrochemical phenomenon?
2
Q13
Explain [Co(NH3)6]3+ is an inner orbital complex where as [Ni(NH3)6]+2 is an 2
outer orbital complex .
Q14
Iron Chromite is used with sodium carbonate in the presence of air to form a 1+1
yellow coloured compound (A). On acidification the compound (A) forms an
orange coloured compound (B) which is strong oxidising agent. Identify.
Q15
(i)
The Compound (A) and (B)
(ii)
Write balanced equation for each step.
Arrange the compound in increasing order of reactivity towards SN2 2
displacement and justify your answer.
1-Bromo-3-methyl butane, 2-Bromo-2-methylbutane and
3- Bromo-2-methylbutane
Q16
Write the formula of main product formed in the following
-2-
2
(a) (CH3)2CHCl
Na
dry ether
(b) CH3Br + AgF
(c) CH3CH2Br + NaI
(d) C6H5N2Cl
dry acetone
Cu/HCl
Q17
Give an example of each of homopolymer and copolymers.
2
Q18
Write the chemical equation for preparing sodium soap from glyceryl palmitate. 2
Give one advantage of soap over detergents.
(C15H31COO)3C3H5
Q19
0.6 mL of acetic acid, having density 1.06 mL-1, is dissolved in 1 L of water. 3
The depression in freezing point observed for this strength of acid was 0.02050C.
Calculate von’t Hoff factor.
Q20
Represent the cell in which the following reaction takes place.
Ni(s) + 2Ag+ (0.002M)
3
Ni2+ (0.160M) + 2Ag (s)
Calculate its Ecell if E0Cell= 1.05V
Q21
(a) Why does physorption decreases with the increase of temperature.
1
(b) Why is the ester hydrolysis slow in the beginning and become faster some 1
time?
Q22
Q23
(c) What is the role of desorption in the process of catalysis?
1
(a) What is role of depressant in froth floatation process?
1
(b) State the role of cryolite in the metallurgy of aluminum.
1
(c) Explain Van Arkel Method.
1
(a) Why ZnCl2 is white in colour?
1
(b) Chromium group elements have the highest melting points in their respective 1
series.
(c) Transition elements generally shows variable oxidation states.
Q24
1
(a) Give one chemical test to distinguish the following
(i) CH3CHO and HCHO
1
(ii) Tert. butyl alcohol and n-butyl alcohol
1
(b) Arrange the following in order of increasing reactivity towards Lucas reagent 1
butan-1-ol, butan-2-ol,
-3-
2-methylpropan-2-ol
Q25
Complete and balance the following equation
(i) XeF4 + SbF5
1
(ii) P4 + KOH + H2O
1
(iii) Cu + Cold dil HNO3
1
OR
Arrange the following in the order of property indicated for each set.
Q26
Q27
(a) HF, HCL, HBr, HI (Increasing acid strength)
1
(b) N, P, As, Sb, Bi (Increasing order of +5 oxidation state)
1
(c) H2O, H2S, H2Se. H2Te (increasing order of boiling point)
1
Account for the following
(a) Ethylamine is soluble in water wherever aniline is not.
(b) Methylamine in water reacts with ferric chloride to precipitate hydrated
ferric oxide.
(c) Although amino group is o-and p-directing in aromatic eletrophilic
substitution reactions, aniline on nitrogen gives a substantial amount of m-nitro
aniline.
(a) What is the effect of denaturation on the structure of proteins?
1
(b) How do you explain the amphoteric behavior of amino acids?
1
1
1
1
(c) What products would be formed when a nuclotide from DNA containing 1
thymine is hydrolysed?
Q28
The decomposition of A into product has value of K as
5
4.5 x 10-3 S-1 at 10oc and energy of activation 60 kJ mol-1. At what temperature
would k be 1.9 x 104 S-1.
OR
For a certain chemical reaction A + 2B
2C + D
The experimentally obtained information is tabulated below.
Experiment
[Ao]
[Bo]
Initial
reaction
1
.30
.30
.096
2
.60
.30
.384
3
.30
.60
.192
4
.60
.60
.768
-4-
rate
of
For this reaction
(i)
5
derive the order of reaction with respect to both the reactants A and
B
Q29
(ii)
Write rate of law
(iii)
calculate the value of rate constant K
(iv)
write the expression for the rate of reaction in terms of A and C
(i) PH3 has lower boiling point than NH3. Why?
1
(ii) Explain why ClF3 exists whereas FCl3 does not.
1
(iii) H2S is acidic while H2Ois neutral?
1
(iv) SF6 is a well known compound but SCl6 is not known explain.
1
(v) How XeOF4 prepared?
1
OR
Q30
A translucent white waxy solid (A) on heating in an inert atmosphere is 5
converted to its allotropic forms (B). Allotrope (A) on reaction with very dilute
aqueous KOH liberates a highly poisonous gas (C) having rotten fish smell with
excess of chlorine. (A) Forms (D) which hydrolysis to compound (E). Identify
compounds (A) to (E) and give chemical reactions involved.
(a) Complete the following by providing A and B
1+1
(i) C6H5NH2 NaNO2
A
CuBr/HBr
B
HCl OoC
(ii) CH3NH2 +CHCl3 + KOH (alc)
A+B
(b) (i) What happens when ethylalcohol is heated with iodine and sodium 1+1+1
hydroxide.
(ii) Methyl bromide is treated with formaldehyde followed by hydrolysis.(
Give equation only )
(iii) Give an example of Williamson’s synthesis.
OR
An organic compound A having molecular formula C9H10O forms an orange red
precipitate B With 2,4-DNP reagent compound A gives yellow precipitate C
when heated in presence of iodine and NaOH along with a colourless compound
A does not reduce Tollen’s reagent or Fehling solution nor does it decolourise
bromine water on drastic oxidation of A with chromic acid a carboxylic acid E
of molecular formula C7H6O2 is formed Deduce the structures of organic
compounds A to E.
-5-
5