IISER Chemistry - Chemistry of s and p-Block elements
Exam Duration: 45 Mins Total Questions : 30
which one of the following statements is true:
- (a)
s-and p-block elements are known as representation
- (b)
d-block elements are known as inner-transitions elements
- (c)
f-block elements are known as inner-transitions elements
- (d)
all of the above
P4O10 has
- (a)
12 P-O bonds and 4 P=Obonds
- (b)
8 P-O bonds and 4 P=O bonds
- (c)
12 P-O bonds and 3 P=Obonds
- (d)
None of the above
NO2 is evolved when
- (a)
NH4NO3 is heated
- (b)
HNO3+P2O5 is heated
- (c)
2NO+N2O4 is heated
- (d)
Pb(NO3)2 is heated
The oxiding ability of perhalates follow th order:
- (a)
CIO4<BrO4>IO4
- (b)
CIO4<BrO4>IO4
- (c)
IO4<BrO4>ClO4
- (d)
None of the above
Pick out incorrect statement in the following?
- (a)
Diamond has a higher density than graphite
- (b)
Diamond is a good conductor of electricity
- (c)
Graphite has a layered structure
- (d)
Graphite is good conductor of electricity
In photography we use
- (a)
Ag2O
- (b)
AgCl
- (c)
AgBr
- (d)
AgNO2
In case of nitrozen, NCL3 is possible but not NCl5 while in case of phosphorous,PCl3 as well as PCl5 are possible is due to
- (a)
availability of vacant-orbital in p but not in N
- (b)
lower electronegativity of P than N
- (c)
lower tendency of H bond formation in P than N
- (d)
occur of P in solid while N in gaseous state at room temperature
In general a salt dissolves in water, when
- (a)
\(\Delta H\) hydration = \(\Delta H\) lattice energy
- (b)
\(\Delta H\) hydration < \(\Delta H\) lattice energy
- (c)
\(\Delta H\) hydration > \(\Delta H\) lattice energy
- (d)
None of these
Which of the following elements can be involved in \(p\pi-d\pi\)bonding?
- (a)
Carbon
- (b)
Nitrogen
- (c)
Phosphorus
- (d)
Boron
Bond dissociation enthalpy of E-H (E-elements) bonds is given below.Which of the compounds will act as strongest reducing agent?
| Compound | NH3 | PH3 | AsH3 |
SbH3 |
| \(\Delta_{diss}(E_H)/kJ\ mol^{-1}\) | 389 | 322 | 297 | 255 |
- (a)
NH3
- (b)
PH3
- (c)
AsH3
- (d)
SbH3
Which of the following statements wrong?
- (a)
Single N-N bond is stronger than the single P-P bond
- (b)
PH3 can act as a ligand in the formation of coordination compound with transition elements
- (c)
NO2 is paramegnetic in nature
- (d)
Covalency of nitrogen in N2O5 is four
Nitrogen is a relatively less active than phosphorus because
- (a)
its atom has a stable electronic configuration
- (b)
it has small atomic radius
- (c)
its electronegativity is fairly high
- (d)
Dissociation energy of its molecule is fairly high
Red phosphorus is chemically less reactive because
- (a)
it does not contain P-P bonds
- (b)
it does not contain tetrahedral P4 molecules
- (c)
it does not catch fire in air even upto 4000C
- (d)
it has a polymeric structure
Holme's signal consist of
- (a)
NH3
- (b)
PH3
- (c)
PH5
- (d)
P2O5
NH3 form hydrogen bond while PH3 does not form hydrogen bond is because of
- (a)
small size of nitrogen atom
- (b)
high value of electronegativity of N atom
- (c)
Both (a) and (b)
- (d)
None of the above
The rare gases are unreactive because they
- (a)
have the same number of electrons
- (b)
have an atomicity of one
- (c)
are gases with low densities
- (d)
have stable electronic configuration or closed valence shell
Out of these three (i)XeO3 (ii)XeOF4 and (iii)XeF6, the molecules having same number of lone pairs on Xe are
- (a)
(i) and (ii)
- (b)
(i) and (iii)
- (c)
(ii) and (iii)
- (d)
(i), (ii) and (iii)
One mole of fluorine reacts with two moles of hot and concentrated KOH.The products formed are KF, H2O and O2.The molar ratio of KF, H2O and O2 respectively is
- (a)
1:1:2
- (b)
2:1:0.5
- (c)
1:2:1
- (d)
2:1:2
A gas X is passed through water to form a saturated solution.The aqueous solution on treatment with AgNO3 gives a white precipitate.
The saturated aqueous solution also dissolves Mg ribbon with evolution of colourless gas Y.X and Y are respectively
- (a)
CO2, Cl2
- (b)
Cl2, CO2
- (c)
Cl2,H2
- (d)
H2, Cl2
Asthma patients use a mixture of ........ for respiration.
- (a)
O2 and Kr
- (b)
O2 and He
- (c)
O2 and Ar
- (d)
O2 and Ne
Which of the following properties of alkali metals increase with increase in atomic number?
- (a)
atomic radius
- (b)
first ionisation energy
- (c)
electronegativity
- (d)
hydration energy of the univalention
We cannot store Na metal under
- (a)
alcohol
- (b)
kerosene
- (c)
toluene
- (d)
benzene
What is the best description of the change that occurs when \(Na_2O\) (s) is dissolved in water?
- (a)
Oxidation number of sodium decreases
- (b)
oxide ion accepts sharing in a pair of electrons
- (c)
oxide ion donates a pair of electrons
- (d)
oxidation number of oxygen increases
Lif is almost insoluble in water whereas LiCl is soluble not only in water but also in acetone. This is because
- (a)
of high hydration enthalpy of \(Li^+\)
- (b)
of low hydration enthalpy of \(Li^+\)
- (c)
of more ionic character in LiCl
- (d)
None of the above
Match the following and choose the correct option.
| Column I | Column II |
| A. BF4- B. AlCl3 C. SnO D. PbO2 |
p. oxidation state of central atom is +4 q. Lewis acid r. Can be further oxidised s. Tetrahedral shape |
- (a)
A B C D q s p r - (b)
A B C D p r q s - (c)
A B C D s q r p - (d)
A B C D r q p s
The molecular composition of mica is
- (a)
NaAlSiO4 . 3H2O
- (b)
K2O . 3Al2O3 .6SiO2 . 2H2O
- (c)
K2HAl(SiO4)3
- (d)
NaK . SiO4 . 10H2O
Borazole is obtained by reaction of
- (a)
NH3 + B2H6 in 2 : 1 ratio
- (b)
NH3 + B2H6 in 1 : 2 ratio
- (c)
NH3 + B2H6 in 2 : 4 ratio
- (d)
NH3 + B2H6 in 4 : 1 ratio
\(KO_2\) is used in space and submarines because it
- (a)
absorbs \(CO_2\) and increases \(O_2\)
- (b)
absorbs moisture
- (c)
absorbs \(CO_2\)
- (d)
produce ozone
A metal M forms water soluble \(MSO_4\) and inert MO. MO in aqueous solution forms insoluble \(M(OH)_2,\) soluble in NaOH. Metal M is
- (a)
Be
- (b)
Mg
- (c)
Ca
- (d)
Sr
Aluminium chloride exists as dimer, Al2Cl6 in solid state as well as in solution of non-polar solvent such as benzene. When dissolved in water, it gives
- (a)
Al3+ + 3Cl-
- (b)
[Al(H2O)6]3+ + 3Cl-
- (c)
[Al(OH)6]3- + 3HCl
- (d)
Al2O3 + 6HCl
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