The p-Block Elements eamcet
mcq’s
1. On addition of conc.
H2SO4 to a chloride salt, colourless fumes are evolved
but
in case of iodide salt, violet fumes come out. This is because
(i)
H2SO4 reduces HI to I2
(ii)
HI is of violet colour
(iii)
HI gets oxidised to I2
(iv)
HI changes to HIO3
2. In qualitative analysis
when H2S is passed through an aqueous solution of
salt
acidified with dil. HCl, a black precipitate is obtained. On boiling the
precipitate
with dil. HNO3, it forms a solution of blue colour. Addition of excess
of
aqueous solution of ammonia to this solution gives _________.
(i)
deep blue precipitate of Cu (OH)2
(ii)
deep blue solution of [Cu (NH3)4]2+
(iii)
deep blue solution of Cu(NO3)2
(iv)
deep blue solution of Cu(OH)2.Cu(NO3)2
3. In a
cyclotrimetaphosphoric acid molecule, how many single and double
bonds
are present?
(i)
3 double bonds; 9 single bonds
(ii)
6 double bonds; 6 single bonds
(iii)
3 double bonds; 12 single bonds
(iv)
Zero double bonds; 12 single bonds
4. Which of the following
elements can be involved in pπ–dπ bonding?
(i)
Carbon
(ii)
Nitrogen
(iii)
Phosphorus
(iv)
Boron
6. Affinity for hydrogen
decreases in the group from fluorine to iodine. Which of
the
halogen acids should have highest bond dissociation enthalpy?
(i)
HF
(ii)
HCl
(iii)
HBr
(iv)
HI
8. On heating with
concentrated NaOH solution in an inert atmosphere of CO2,
white
phosphorus gives a gas. Which of the following statement is incorrect
about
the gas?
(i)
It is highly poisonous and has smell like rotten fish.
(ii)
It’s solution in water decomposes in the presence of light.
(iii)
It is more basic than NH3.
(iv)
It is less basic than NH3.
9. Which of the following
acids forms three series of salts?
(i)
H3PO2
(ii)
H3BO3
(iii)
H3PO4
(iv)
H3PO3
10. Strong reducing
behaviour of H3PO2 is due to
(i)
Low oxidation state of phosphorus
(ii)
Presence of two –OH groups and one P–H bond
(iii) Presence of one –OH group and two P–H
bonds
(iv)
High electron gain enthalpy of phosphorus
11. On heating lead nitrate
forms oxides of nitrogen and lead. The oxides formed
are
______.
(i)
N2O, PbO
(ii)
NO2, PbO
(iii)
NO, PbO
(iv)
NO, PbO2
12. Which of the following
elements does not show allotropy?
(i)
Nitrogen
(ii)
Bismuth
(iii)
Antimony
(iv)
Arsenic
13. Maximum covalency of
nitrogen is ______________.
(i)
3
(ii)
5
(iii)
4
(iv)
6
14. Which of the following
statements is wrong?
(i)
Single N–N bond is stronger than the single P–P bond.
(ii)
PH3 can act as a ligand in the formation of coordination compound
with
transition elements.
(iii)
NO2 is paramagnetic in nature.
(iv)
Covalency of nitrogen in N2O5 is four.
17. On heating ammonium dichromate
and barium azide separately we get
(i)
N2 in both cases
(ii)
N2 with ammonium dichromate and NO with barium azide
(iii)
N2O with ammonium dichromate and N2 with barium azide
(iv)
N2O with ammonium dichromate and NO2 with barium azide
18. In the preparation of
HNO3, we get NO gas by catalytic oxidation of ammonia.
The
moles of NO produced by the oxidation of two moles of NH3 will be ______.
(i)
2
(ii)
3
(iii)
4
(iv)
6
19. The oxidation state of
central atom in the anion of compound NaH2PO2 will
be
______.
(i)
+3
(ii)
+5
(iii)
+1
(iv)
–3
22. Hot conc. H2SO4 acts as
moderately strong oxidising agent. It oxidises both
metals
and nonmetals. Which of the following element is oxidised by conc.
H2SO4
into two gaseous products?
(i)
Cu
(ii)
S
(iii)
C
(iv)
Zn
23. A black compound of
manganese reacts with a halogen acid to give greenish
yellow
gas. When excess of this gas reacts with NH3 an unstable trihalide is
formed.
In this process the oxidation state of nitrogen changes from _________.
(i)
– 3 to +3
(ii)
– 3 to 0
(iii)
– 3 to +5
(iv)
0 to – 3
24. In the preparation of
compounds of Xe, Bartlett had taken O2
+
Pt F6
–
as a base
compound.
This is because
(i)
both O2 and Xe have same size.
(ii)
both O2 and Xe have same electron gain enthalpy.
(iii)
both O2 and Xe have almost same ionisation enthalpy.
(iv)
both Xe and O2 are gases.
27. Which of the following
is isoelectronic pair?
(i)
ICl2, ClO2
(ii)
BrO2– , BrF2+
(iii)
ClO2, BrF
(iv)
CN–, O3
