P-block
Complete the following reactions :
(ii) N4H Cl (aq)
+ NaNO2
(aq)
¾¾®
2. (i) NH2CONH2 + H2O ¾¾®
(ii) FeCl3 (aq) + NH4OH ¾¾®
3. (i) Ca3 P2 + H2 O (l) ¾¾®
(ii) I2 + HNO3 (conc.) ¾¾®
4. (i) Ba(N3)2¾¾heat®
(ii) 4H3PO3¾¾heat®
5. (i) PH4I + KOH ¾¾®
(ii) HgCl2 + PH3 ¾¾®
6. (i) PCl3 + 3H2O ¾¾®
(ii) S + H2SO4 (conc.) ¾¾®
7. (i) Al2O3(s) + NaOH
(aq) + H2O(l) ¾¾®
(ii) HCl + O2 + CuCl¾¾¾¾®
8. (i) Ca(OH)2 + Cl2 ¾¾®
(ii) XeF4 + H2O ¾¾®
9. (i) Na2SO3 + Cl2 + H2O ¾¾®
(ii) NaHCO3 + HCl¾¾®
10. (i) XeF6 + H2O Completehydrolysis¾¾¾¾®
(ii) XeF6 + H2OPartialhydrolysis
¾¾¾¾®
11. (i) NO3– + Fe2+ + H+ ¾¾®
(ii) Zn + HNO3 (dil) ¾¾®
12. (i) Zn + HNO3 (conc) ¾¾®
(ii) P4 + HNO3 (conc) ¾¾®
13. (i) NH3 + O2¾¾Pt/Rh®
(ii) P4 + NaOH + H2O ¾¾®
14. (i) P4 + SOCl2 ¾¾®
(ii) P4 + SO2Cl2 ¾¾®
15. (i) PbS + O3 ¾¾®
(ii) KI + H2O + O3 ¾¾®
16. (i) MnO4– + SO2 + H2O ¾¾®
(ii) Zn + HNO3(dil)¾¾®
17. (i) NH3 (Excess) +
Cl2
¾¾®
(ii) NH3 + Cl2 (Excess) ¾¾®
18. (i) Cl2 + NaOH
(cold and dil) ¾¾®
(ii) Cl2 + NaOH
(hot &conc) ¾¾®
19. (i) Fe + HCl¾¾®
(ii) Cl2 + F2 (Excess) ¾¾®
20. (i) U + ClF3 ¾¾®
(ii) FeSO4 + H2SO4 + Cl2 ¾¾®
21. (i) How is HNO3 prepared
commercially?
(ii) Write chemical equations
of the reactions involved.
(iii) What
concentration by mass of HNO3 is obtained?
22. (i) How does O3 react with
lead sulphide? Write chemical equation.
(ii) What happens
when SO2
is
passed in acidified KMnO4 solution?
23. An unknown salt X
reacts with hot conc. H2SO4 to produce
a brown coloured gas which intensifies on addition on copper turnings. On
adding dilute ferrous sulphate solution to an aqueous solution of X and then
carefully adding conc. H2SO4 along the
sides of the test tube, a brown complex Y is formed at the interface between
the solution and H2SO4. Identify X and
Y and write the
chemical equation involved in the reaction.
24.A transluscent
while waxy solid (A) on heating in an inert atmosphere is converted to its
allotropic form (B), Allotrope (A) on reaction with very dilute aqueous NaOH
liberates a highly poisonous gas (C) having a rotten fish smell, with excess of
chlorine forms D which hydrolyses to form compound (E). Identify the compounds
(A) to (E).
25. Write balanced
equation for the following reactions :
(a) Zn is treated
with dilute HNO3.
(b) NaCl is heated
with H2SO4 in the
presence of MnO2.
(c) Iodine is treated
with conc. HNO3.
25. X2 is a
greenish yellow gas with pungent offensive smell used in purification of water.
It partially dissolves in H2O to give a solution which turns
bluelitmus red. When X2 is passed through NaBr Solution, Br2 is
obtained.
(a) Identify X2, name the
group to which it belongs.
(b) What are the
products obtained when X2 reacts with H2O?
Writechemical equation.
(c) What happens when
X2
reacts
with hot and conc. NaOH? Giveequation.
26.How is PH3 prepared
in the laboratory? How is it purified? How does the solution of PH3 in water
react on irradiation with light and on absorption in CuSO4? How can
you prove that PH3 is basic in nature?Write the chemical
equations for all the reactions involved.
27. A white waxy,
translucent solid, M, insoluble in water but soluble in CS2,glows in
dark. M dissolves in NaOH in an inert atmosphere giving a poisonous gas (N).
Also M catches fire to give dense white fumes of Q :
(a) Identify M, N and
Q and write the chemical equations of the reactions involved.
(b) M exists in the
form of discrete tetrahedral molecules. Draw its structure.
(c) M on heating at
573 K is changed into other less reactive form, Q, which is non-poisonous,
insoluble in water as well as in CS2 and does not glow in
dark, Identify Q and draw its structure.
D
& F- block
1.The stability of Cu2+ (aq) is
more than that of Cu+ (aq). Why?
2. Indicate the steps
in the preparation of
(a) K2Cr2O7 from
Chromite ore.
(b) KMnO4 from
Pyrolusite ore.
3.(a) Why do
transition metals show high melting points?
(b) Out of Fe and Cu,
which one would exhibit higher melting point?
4. Describe giving
reason which one of the following pairs has the property
indicated :
(a) Cr2+ or Fe2+ (stronger
reducing agent).
(b) Co2+ or Ni2+ (lower
magnetic moments).
5. Of the ions Co2+, Sc3+, Cr3+ which one
will give colourless aqueous solution and how will each of them respond to magnetic
field and why?
6. For the first row
transition metals the enthalpy of atomisation value are :
ScTi V
Cr Mn Fe
Co Ni Cu
Zn
∆aH/kJ mol–1 326 473
515 397 281 416 425 430 339 126
Assign reason for the
following :
(a) Transition elements
have higher values of enthalpies of atomisation.
(b) The enthalpy of
atomisation of zinc is the lowest in 3d - series.
7. Account for the
following :
(a) Copper shows its
inability to liberate hydrogen gas from the dilute acids.
(b) Scandium (Z = 21)
does not exhibit variable oxidation states.
8. Copper (I)
compounds undergo disproportionation. Write the chemical equation for the
reaction involved and give reason.
9.Account for the
following :
(a) La(OH)3 is more
basic than Lu(OH)3
(b) Zn2+ salts are white.
(c) Cu(I) compounds
are unstable in aqueous solution and undergodisproportination.
10. Describe the
oxidising action of potassium dichromate with following. Writeionic equations
for its reaction with.(a) Iodide ion (b) Iron (II) (c) H2S.
11. (a) Deduce the
number of 3d electrons in the following ions :
Fe3+, Cu2+ and Sc3+.
(b) Why do transition
metals form alloys.
(c) Write any two
characteristics of interstitial compounds.
12.(a) For M2+/M and M3+/M2+ systems,
the Evalues for some
metals are as follows :
Cr2+/Cr = –
0.9V and Cr3+/Cr2+ = – 0.4V
Mn2+/Mn = –
1.2 V and Mn3+/Mn2+ = + 1.5V
Fe2+/Fe = –
0.4V and Fe3+/Fe2+ = + 0.8V
Use this data to
comment upon :
(i) the stability of
Fe3+
in
acid solution as compared to that of Cr3+ and Mn3+
(ii) the ease with
which iron can be oxidised as compared to a similar process for either chromium
or manganese.
(b) How is the
variability in oxidation states of transition metals different from that of the
non-transition metals? Illustrate with examples.
13.When a white
crystalline compound A is heated with K2Cr2O7 and conc.H2SO4, a
reddish brown gas B is evolved, which gives a yellow coloured solution C when
passed through NaOH. On adding CH3COOH and(CH3COO)2 Pb to
solution C, a yellow coloured ppt. D is obtained. Also on heating A with NaOH
and passing the evolved gas through K2HgI4 solution,
a reddish brown precipitate E is formed.Identify A, B, C, D and E and write the
chemical equations for the reactions involved.
14.A green compound
‘A’ on fusion with NaOH in presence of air forms yellow compound ‘B’ which on
acidification with dilute acid, gives orange solution of compound ‘C’. The
orange solution when reacted with equimolarammonuim salt gives compound ‘D’
which when heated liberates nitrogen gas and compound ‘A’. Identify compounds A
to D and write the chemical
equation of the
reactions involved.
[Hint :‘A’ =
CrO3; ‘B’ = Na2CrO4; ‘C’ = Na2Cr2O7 ‘D’ = (NH4)2 Cr2O7
15. Assign reasons
for the following :
(a) There is no
regular trends in E° values of M2+/M systems in 3d series.
(b) There is gradual
decrease in the ionic radii of M2+ ion in 3d series.
(c) Majority of
transition metals form complexes.
(d) Ce3+ can be
easily oxidised to Ce4+
(e) Tantalum and
palladium metals are used to electroplate coinage metals.
16. Account for the
following :
(a) Actinoids display
a variety of oxidation states.
(b) Yb2+ behaves as
a good reductant.
(c) Cerium (iv) is a
good analytical reagent.
(d) Transition metal
fluorides are ionic in nature while chlorides and bromides are covalent in
nature.
(e) Hydrochloric acid
attacks all the actinoids.
17. Explain by giving
suitable reason :
(a) Co(II) is stable
in aqueous solution but in the presence of complexing agent it is readily
oxidised.
(b) Eu2+, Yb2+ are good
reductants whereas Tb4+ is an oxidant.
(c) AgCl dissolves in
ammonia solution
(d) Out of Cr2+ or Fe2+, which
one is a stronger reducing agent?
(e) The highest
oxidation state is exhibited in oxoanions of a transition metal.
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