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Contined Geo Sint (Man
Examination-2025 BGSP-A-CMS
CHEMISTRY
Paper - I
Time Allowed : Three Hours Maximum Marks : 200
Question Paper Specific Instructions
Please read each of the following instructions carefully before attempting
questions :
There are ELEVEN questions divided under SIX sections.
Candidate has to attempt SIX questions in all.
The ONLY question in Section A is compulsory.
Out of the remaining TEN questions, the candidate has to attempt FIVE, choosing ONE
from each of the other Sections B, C, D, E and F.
The number of marks carried by a question / part is indicated against it.
Neat sketches are to be drawn to illustrate answers, wherever required. These shall be
drawn in the space provided for answering the question itself:
Ute _niioned, symbols and notations have their usual standard meanings.
- sun old aa, if necessary, and indicate the same clearly.
Attempts of questions shall be counted in sequential order. Unless struck off, attempt of a
question shall be counted even if attempted partly.
Any page or portion of the page left blank in the Question-cum-Answer ( QCA) Booklet must
be clearly struck off:
Answers must be written in ENGLISH only.
BGSP-A-CMS 1
Answer all of the following :
Ql. (a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
(fusi fe"cin2-099 bemdmod
(SEORIONGA
(Compulsory Section)
5x10=50
Which defect does silver chloride show and why ? 5
Which isomerism do [(NH3)sCoONO]Cl, and [(NHg3)s;CoNOgICly
complexes show and why ?
Arrange the following metals in descending order of their trans-effect
with proper justification :
Nil, pe, pall
Phenolphthalein shows red colour in presence of dilute alkali. However,
if treated with excess of concentrated alcoholic alkali, the red colour first
produced disappears. Explain how.
Calculate the solubility product of silver chromate at a particular
temperature, at which its solubility is 2-5 x 107? gram litre-!.
[Given : The relative molecular mass of silver chromate is 331-728]
Determine the colour change interval for the indicator, diphenylamine, at
298 K.
[Given : E° for diphenylamine is + 0-756 V]
Why can Eriochrome Black T not be used to indicate the end point of a
direct EDTA titration of calcium ?
Which metals of the following have the greatest tendency to form metal
clusters ? Justify your answer.
Gi) ~=V,Nb, Ta
Gi) Zr, V,Nb
(iii) Cr, Mo, Tc
(iv) Nb, Mo, Tc
BGSP-A-CMS 2
(i) Complete the following equations :
9 4 12
9
4136 + 216 > 60+ ?
16 2
9
80 + 781 —> 7 + ?
27 80+ 1
9
. ? _ 151 + oh
23. 4 26.
11Na + He —~+ 9009 ?
4 14 N 17
gHe + 7N ? + 80
0) Why is the first ionization enthalpy of 5d series elements higher than
that of 3d and 4d series elements ?
BGSP-A-CMS 3
SECTION B
Attempt any one question :
Q2.
Q3.
(a)
(b)
(c)
(a)
(b)
How does BaTiO3 show local ion displacement ? Also mention its
electrical behaviour. 15
What should be the possible structure of binary hydrides and oxides of
the following according to the composition ranges provided in brackets? 10
Gi) =LuHy, (1:85 - 2-23)
(ii) ErHy (2:82 - 3-0)
(iii) TiO, (0-7 - 1-25)
(iv) VO x (0-9 - 1:20)
(v) TiO, (1-9 - 2:0)
How will you synthesize YBagCu,O07 quaternary oxide ? Explain with
chemical reaction. 5
50 mL of 0-1M phosphoric (V) acid is being titrated with 0-1M
potassium hydroxide solution at 25°C. Calculate the pH values at (i) the
first equivalence point, (ii) the second equivalence point, and also at
(iii) the third equivalence point.
Draw the titration curve. Suggest suitable indicator(s) in each stage of
this titration. 15
[Given : K, = Primary dissociation constant of phosphoric (V)
acid = 7:5 x 107
Ky = Secondary dissociation constant of phosphoric (V)
acid = 6-2 x 1078
Kg = Tertiary dissociation constant of phosphoric (V)
acid = 5-0 x 10-18
Ionic product of water at 25°C = 1:1 x 10714]
What is meant by salt hydrolysis ? Calculate (i) the hydrolysis constant,
(ii) the degree of hydrolysis in %, and (iii) the pH of a 0-01 molar
solution of sodium acetate at 25°C. 15
[Given : K, for acetic acid = 1:8 x 10~° and ionic product of water at
25°C = 11x10"
BGSP-A-CMS 4
SECTION C
Attempt any one question :
Q4. (a)
(b)
(c)
Q5. ()
(b)
()
What is Wilkinson’s catalyst ? Outline the catalytic cycle for the
hydrogenation of alkene as catalysed by this catalyst. 15
What is 18-electron rule ? Confirm that the Cr centre in
[ obeys the 18-electron rule, but the Rh in
[பம்பு] does not. 10
What are magic numbers ? 2087) is very stable. Explain why. 5
What will be the structure and geometry of the given compounds ? 10
¢ [0||
क) ത്തി”
96
(iv)
Arrange the following complexes based on their increasing ligand field
strength with reason.
[சபி மணமே and [Cr(CN)gl>- 10
(where dtp = diethyldithiophosphate)
A small amount of a solution containing 24 (ty = 15 hours)
is injected into the bloodstream of a man. The initial activity is
2 x 103 counts 56008471, The activity of 1 cm® of blood sample taken
from the man after 5 hours is 16 counts minute~!. Find the total volume
of blood of the man. 10
BGSP-A-CMS 5
SECTION D
Attempt any one question :
Q6.
Q7.
(a)
(b)
(a)
(b)
(ce)
Consider the gravimetric estimation of sulphate as barium sulphate
through filtering crucible method.
(i) Mention the principle of this estimation with the requisite
equation along with the ignition temperature of the precipitate.
Gi) Find out the Gravimetric Factor (GF) of sulphate in barium
sulphate.
[Given : Atomic weight of Barium = 137-33
Atomic weight of Sulphur = 32:064
Atomic weight of Oxygen = 15-999]
(ii) How can the experimentally obtained results be lower or higher
than the true value ? Suggest some measures in this respect so as
to obtain a satisfactory result. 15
Calculate the potential of a solution at the equivalence point in the
titration of 25 mL of 0:1 N FeSO, solution with 0-1 N Cr o7- solution
at 25°C. 15
The pH of the solution may be supposed buffered to pH 1:0 and also
neglect the dilution effect.
? °
[Given : Ee3t/peet =0:77V
E° = 1:36 VI
Cr,07-/Cr3* 36 VI
Explain the thermodynamic and kinetic stability in [Ni(CN),I?,
[Mn(CN),|- and [Cr(CN)gl- complexes. 10
What is the Jahn-Teller effect ? How does it affect the unsymmetrical
electronic spectra of octahedral complexes of Ni (+III) ? 10
Consider the following redox reaction :
Cl, + 2Fe** —— 2Cr + 2Fe3+
Elucidate the fact that an iron (II) salt is almost completely oxidised by
chlorine at 298 K. 10
s fe)
[Given: E Cly/2cr = 1:36 V
E° =0-77
Fe3* /Fe2+ O77 VI
BGSP-A-CMS 6
SECTION E
Attempt any one question :
Q8. (a) What are redox indicators ? Mention the criteria of a suitable redox
indicator. What is ferroin ? Draw the structures of ferroin in oxidised
and reduced forms. Mention the colour(s) in these two forms. 15
(b) On the basis of Lanthanide contraction, explain the following : 15
(i) Nature of bonding in LugO3 and LagO3
(ii) | Trends in the stability of Oxo salts of lanthanides from La to Lu
Gii) Stability of the complexes of Lanthanides
(iv) Radii of 4d and 5d block elements
(v) Trends in acidic character of Lanthanide oxide
Q9. (a) Draw the average binding energy per nucleon (in MeV) against atomic
mass number plot. Mention the salient features of this plot. On the basis
of this plot, how will you explain the chances of nuclear fusion and
fission processes ? 15
(b) Outline the principle for the estimation of Ca2* and Mg?* in a mixture
(solution) employing EDTA as a titrant.
[Mentioning of the names of buffers, pH values, indicators, specification
of colour changes, basis of the calculations are required]
Draw the structures of Ca2+ - EDTA and Mg”* - EDTA complexes. 15
BGSP-A-CMS 7
SECTION F
Attempt any one question :
Q10. (a)
(b)
(c)
Ql1l. (a)
(b)
(c)
What are the metal-ion indicators ? Mention the requisites of a
metal-ion indicator for use in the visual detection of end points. 10
Explain masking and demasking with a suitable example with
particular reference to complexometric EDTA-based titration. 10
Write down the electronic configuration for La®*, Gd®* and Lu®* and
calculate the magnetic moment for those electronic configurations. 10
What are the main components of Geiger-Muller counter ? How does a
Geiger-Muller counter detect the presence of radiation ? 15
oO
Cl. Pe” NH, | Thiourea (tu) a thiourea (tu)
B
a~ ™ NH; Slight excess
Cl NH. aie
N73 Thiourea (tu) Thiourea (tu) :
Pt >C No reaction
H3N 4Oo™N Cl excess
Identify A, B and C in the above reactions. Justify your answer. 5
Many octahedral complexes of Co?* are pale pink in colour, while
tetrahedral complexes of Co* are intensely blue in colour. Why ? 10
BGSP-A-CMS 8
