CBSE Set Q Chemistry Sample Test Papers For Class 12th for students online
You are on Set no 1 Q.No. 1 to 20
Time allowed : 3 hours
Maximum Marks : 70
General Instructions :
(i) All questions are compulsory.
(ii) Marks for each question are indicated against it.
(iii) Question number 1 to 10 are very short-answer questions each of 1 mark. Answer them in about one sentence each.
(iv) Question number 11 to 26 are short-answer questions of 2 marks. Answer them in not more than 30 words each.
(v) Question number 27 to 32 are short-answer questions of 3 marks. Answer them in not more than 40 words each.
(vi) Question number 33 to 34 are long-answer questions of 5 marks each. Answer them in not more than 70 words each.
(vii) Use Log tables, if necessary.
(viii) Please write down the serial number of the question before attempting it.
Q1) Write the MO electronic
configuration of a diatomic molecule having a bond order of three ? (Marks
Q2) What are non-stoichiometric
compounds ? (Marks 1)
Q3) Complete the nuclear
reaction expression ? (Marks 1)
Q4) Write the IUPAC name of
Q5) Why do noble gases form
compounds with fluorine and oxygen only ? (Marks 1)
Q6) Why is hydrochloric acid
not used to acidify a permanganate solution in volumetric estimations of Fe2+
or C2O42-? (Marks 1)
Q7) How many isomers are
there for the complex [Co(NH3)4 Cl2]Cl?
Q8) Why are carbohydrates
generally optically active? (Marks 1)
Q9) Give one important use of
each of the following in pharmacy : (Marks 1)
Q10) Illustrate the function
of mordent's by one example. (Marks 1)
Q11) Predict the structure of
MgO crystal and co-ordination number of its cation in which the cation and anion
radii are equal to 65 pm and 140 pm respectively. (Marks 2)
Q12) With the help of
suitable diagrams, illustrate the two types of non-ideal solutions. (Marks
Q13) What is meant by average
bond energy? In what way is it different from bond energy of a diatomic molecule
? Give suitable examples. (Marks 2)
Q14) Explain Kohlrausch's law
of independent migration of ions. Mention one application of Kohlrausch's law.
Q15) For what concentration
of Ag+ (aq) will the e.m.f. of the given cell be zero at 25oC,
if concentration of Cu2+ (aq) is 0.1 M? (Marks 2)
CU (s) | Cu2+ (0.1 M) || Ag+ (aq) | Ag (s)
[ Given Eo Ag+/Ag = + 0.80 V; Eo Cu2+/Cu = + 0.34 V ]
Q16) (a) Show graphically how
the rate of a first order reaction with only one reactant depends upon the
concentration of the reactant.
(b) Give one example of a first order reaction. (Marks 2)
Q17) For a reaction, the
energy of activation is zero. What is the value of rate constant at 300 K, if k
= 1.6 x 106 s-1 at 280 K ? [ R = 8.31 JK-1 mol-3
] (Marks 2)
Q18) 1.0 x 10-6 g
of radioactive iodine is injected into the blood of a patient. How long will it
take for radioactivity to fall to 10% of the initial value?
[ Given t1/2 for 53I133 = 8.05 days ] (Marks 2)
Q19) Account for the
(i) Formaldehyde gives Cannizaro's reaction whereas acetaldehyde does not.
(ii) Carboxylic acids do not give the characteristic reactions of carbonyl group. (Marks 2)
Q20) How are the following
conversions carried out?
(i) Ethanoic acid to propanoic acid.
(ii) Ethanol to propanone.
Write reaction equations and conditions to support your answer. (Marks 2)
(i) Sandmeyer's reaction
(ii) Kharasch Effect (Marks 2)
Q22) What is 'inert pair effect'? Discuss the oxidation
states of Group 13 elements in relation to this effect. (Marks 2)
Q23) A co-ordination compound has the formula CoCl3.4NH3.
It does not liberate ammonia but precipitates chloride ions as silver chloride.
Give the IUPAC name of the complex and write its structure formula. (Marks
Q24) Write the information asked for in the following
(i) Bakelite : material used for preparation
(ii) Synthetic rubber : monomer unit
(iii) PVC : monomer unit
(iv) Nylon-66 : materials required for preparation. Marks 1)
Q25) "The two strands of DNA are not identical but
are complementary." Explain this statement. (Marks 2)
Q26) Write the structure of adenosine triphosphate
indicating clearly the energy rich bonds. How does this molecule form the source
of energy? (Marks 2)
Q27) Explain how an electron can be considered to have a
particle as well as nature. A moving electron has 4.9 x 10-25 joules
of kinetic energy. Find out its De Broglie wavelength.
(Given h = 6.6x10-34 Js; m = 9.1x10-31 kg) (Marks 3)
Q28) An aqueous solution freezes at 272.4 k, while pure
water freezes at 273.0 K. Determine :
(i) the molality of the solution,
(ii) boiling point of the solution,
(iii) lowering of vapour pressure of water at 298K.
[ Given Kf = 1.86 K kg mol-, Kb = 0.512 K kg mol-1 and vapour pressure of water at 298 K = 23.756 mm Hg ] (Marks 3)
Q29) (a) When NH4NO2 (s) decomposes
at 373 K, it forms N2(g) and H2O(g). The H
for the reaction at one atmosphere pressure and 373k is -223.6 kJ mol-1
of NH4NO4(s) decomposed. What is the value of
E for the reaction under the same conditions?
[ Given R = 8.31 JK- mol-1 ]
(b) Account for the fact that E is numerically bigger H in the above case. (Marks 3)
Q30) What is meant by the colloidal state of matter?
Explain the following terms :
(i) Multi-molecular colloids
(ii) Elector-dialysis (Marks 3)
Q31) An organic compound A having molecular formula, C6H6O
give a characteristic colour with aqueous FeCl3 solution. A on
treatment with CO2 and NaOH at 400 K under pressure gives B which on
acidification gives a compund C. C reacts with acetyl chloride to give D which
is a popular pain-killer. Deduce the structures of A, B, C and D (Marks 3)
Q32) (a) Write the balanced equations for the following
(i) BF3 + LiH
(ii) NH3 + NaOCl
(iii) SiCl4 + H2O
(iv) XeF6 + KF
(b) State the reason for the occurrence of "diagonal relationship" in the periodic table. (Marks 3)
Q33) (a) Write the general formula for nitroalkanes and
for alkyl nitrites.
(b) How are nitroalkanes prepared alkanes?
(c) What happens when :
(i) nitroethane is treated with lithium aluminium hydride,
(ii) nitrobenzene is reduced with hydrogen using copper oxide as catalyst.
(d) Write two use of nitroalkanes, one each in the laboratory and in the industry. (Marks 5)
Q34) (a) (i) What are inner transition elements? Write
their general electronic configuration.
(ii) In what way are the observed oxidation states of the lanthanide's related to their electronic configuration?
(b) Describe the general characteristics of the transition elements with special reference to their tendency to :
(i) exhibit paramagnetism,
(ii) form complex compounds,
(iii) their catalytic behaviour. (Marks 5)