12th Standard Chemistry English Medium Metallurgy Important Questions
Metallurgy
12th Standard
Reg.No. :
Chemistry
Time :
01:00:00 Hrs
Total Marks :
60
60 x 1 = 60
Which of the metal is extracted by Hall-Heroult process?
(a)
Al
(b)
Ni
(c)
Cu
(d)
Zn
Which of the following is not true with respect to Ellingham diagram?
(a)
Free energy changes follow a straight line. Deviation occurs when there is a phase change.
(b)
The graph for the formation of CO2 is a straight line almost parallel to free energy axis.
(c)
Negative slope of CO shows that it becomes more stable with increase in temperature.
(d)
Positive slope of metal oxides shows that their stabilities decrease with increase in temperature.
Concentration of copper glance is done by________.
(a)
leaching
(b)
magnetic separation
(c)
froth flotation
(d)
hydraulic washing
Steel is an alloy of___________
(a)
iron and carbon
(b)
iron and calcium
(c)
copper and carbon
(d)
copper and iron
Which of these is not a monomer for a high molecular mass silicone polymer?
(a)
Me3SiCl
(b)
PhSiCl3
(c)
MeSiCl3
(d)
Me2SiCl2
Which of the following is not sp2 hybridised?
(a)
Graphite
(b)
graphene
(c)
Fullerene
(d)
dry ice
Lewis acid character of boron trihalides is as a follows _______.
(a)
BF3 > BCl3 > BBr3 > BI3
(b)
BCI3 > BF3 > BBr3 > BI3
(c)
BI3 > BBr3 > BCl3 > BF3
(d)
BI3 > BF3 > BCl3 > BBr3
Chemical formula of phosgene is_______.
(a)
COCl2
(b)
CaOCl2
(c)
CaCO3
(d)
COCI
Assertion: Bond dissociation energy of fluorine is greater than chlorine gas Reason: Chlorine has more electronic repulsion than fluorine. Codes:
a) Both assertion and reason are true and reason is the correct explanation of assertion.
b) Both assertion and reason are true but reason is not the correct explanation of assertion
c) Assertion is true but reason is false
d) Both assertion and reason are false
(a)
Both assertion and reason are true and reason is the correct explanation of assertion.
(b)
Both assertion and reason are true but reason is not the correct explanation of assertion
(c)
Assertion is true but reason is false
(d)
Both assertion and reason are false
Which of the following is strongest acid among all?
The high reactivity of fluorine is due to________.
(a)
high ionisation energy
(b)
low bond dissociation energy
(c)
low electron affinity
(d)
high electro negativity
Sc (Z = 21) is a transition element but Zinc (z = 30) is not because _______.
(a)
both Sc3+ and Zn2+ ions are colourless and form white compounds
(b)
In case of Sc, 3d orbital are partially filled but in Zn these are completely filled
(c)
last electron as assumed to be added to 4s level in case of zinc
(d)
both Sc and Zn do not exhibit variable oxidation states
The catalytic behaviour of transition metals and their compounds is ascribed mainly due to _______.
(a)
their magnetic behaviour
(b)
their unfilled d orbitals
(c)
their ability to adopt variable oxidation states
(d)
their chemical reactivity
Identify the paramagnetic species.
(a)
Cu+
(b)
Cr+
(c)
MnO4
(d)
Zn2+
_________ is known as Bayer's reagent.
(a)
Hot dilute alkaline KMnO4
(b)
Cold dilute alkaline KMnO4
(c)
Hot Conc. acidic KMnO4
(d)
Cold Conc. acidic KMnO4
Which one of the following will give a pair of enantiomorphs?
(a)
[Cr(NH3)6][Co(CN)6]
(b)
[Co(en)2Cl2]Cl
(c)
[Pt(NH3)4][PtCl4]
(d)
[Co(NH3)4Cl2]NO2
Formula of tris(ethane-1, 2-diamine)iron(II)phosphate _______.
(a)
[Fe(CH3-CH(NH2)2)3](PO4)3
(b)
[Fe(H2N-CH2-CH2-NH2)3](PO4)
(c)
[Fe(H2N-CH2-CH2-NH2)3](PO4)2
(d)
[Fe(H2N-CH2-CH2-NH2)3]3(PO4)2
The hypothetical complex triamminediaqua chloridocobalt (III)chloride can be represented as _______.
(a)
[Co(NH3)3(H2O)2Cl]Cl2
(b)
[Co(NH)3(H2O)Cl3]
(c)
[Co(NH2)3(H2O)2Cl]
(d)
[Co(NH3)3(H2O)3]Cl3
In an octahedral complex, the (n-1) d orbital are involved in hybridization. The complex is called ________ complex.
(a)
inner orbital
(b)
low spin
(c)
spin paired
(d)
all the above
In a solid atom M occupies ccp lattice and \(\left( \frac { 1 }{ 3 } \right) \) of tetrahedral voids are occupied by atom N. Find the formula of solid formed by M and N ________.
(a)
MN
(b)
M3N
(c)
MN3
(d)
M3N2
The ionic radii of A+ and B− are 0.98 x 10-10 m and 1.81 x 10-10 m. the coordination number of each ion in AB is ________.
(a)
8
(b)
2
(c)
6
(d)
4
In a face centred cubic cell, an atom at the face contributes to the unit cell_______.
(a)
\(\frac{1}{4}\)Part
(b)
1Part
(c)
\(\frac{1}{2}\)Part
(d)
\(\frac{1}{8}\)Part
ABAB type of packing is called _________.
(a)
hexagonal close packing
(b)
cubic close packing
(c)
tetragonal close packing
(d)
none of the above
For a reaction Rate = k[acetone]3/2 then unit of rate constant and rate of reaction respectively is _______.
(a)
(mol L-1 S-1),(mol1/2 L1/2 S-1)
(b)
(mol-1/2 L1/2 s-1),(mol L-1 s-1)
(c)
(mol1/2 L1/2 s-1),(mol L-1 s-1)
(d)
(mol L s-1),(mol1/2 L1/2 s)
In a reversible reaction, the enthalpy change and the activation energy in the forward direction are respectively −x kJ mol-1 and y kJ mol-1. Therefore, the energy of activation in the backward direction is _______.
(a)
(y-x) kJ mol-1
(b)
(x+y) J mol-1
(c)
(x-y) KJ mol-1
(d)
(x+y) x 103J mol-1
For a reaction: aA ⟶ bB, the rate of reaction is doubled when the concentration of A is increased by four times. The rate of reaction is equal to _____.
(a)
k[A]a
(b)
\(k{ \left[ A \right] }^{ \frac { 1 }{ 2 } }\)
(c)
\(k{ \left[ A \right] }^{ \frac { 1 }{ a } }\)
(d)
K[A]
The half-life period of a first order reaction is 69.3 seconds. Its rate constant is ________.
(a)
10-2 s-1
(b)
10-4 s-1
(c)
10 s-1
(d)
102 s-1
What is the decreasing order of strength of bases
OH, NH2- H - C ≡ C and CH3 - CH2-
(a)
OH->NH2- >H-C≡C >CH3-CH2-
(b)
NH2->OH->CH3-CH2- >H-C≡C
(c)
CH3-CH2->NH2->H-C≡C->OH-
(d)
OH->H-C ≡ C->CH3-CH2- >NH2-
Dissociation constant of NH4OH is 1.8 x 10-5 the hydrolysis constant of NH4Cl would be _______.
(a)
1.8 × 10-19
(b)
5.55 × 10-10
(c)
5.55 × 10-5
(d)
1.80 × 10-5
Which among the following has the highest pH?
(a)
1M NH4 OH
(b)
1M HCI
(c)
1M NaOH
(d)
0.1 M NaOH
Henderson equation for a weak acid and its salt is _______.
(a)
pH = pKb+ log (Salt) / (Acid)
(b)
pH = pKa + log (Salt) / (Acid)
(c)
pH = pKa + log (Salt) / (Base)
(d)
pH = pKa + log (Acid) / (Salt)
How many faradays of electricity are required for the following reaction to occur MnO4-→ Mn2+
(a)
5F
(b)
3F
(c)
1F
(d)
7F
While charging lead storage battery _______.
(a)
PbSO4 on cathode is reduced to Pb
(b)
PbSO4 on anode is oxidised to PbO2
(c)
PbSO4 on anode is reduced to Pb
(d)
PbSO4 on cathode is oxidised to Pb
What happens during the electrolysis of molten sodium chloride?
(a)
Cl2 is released at the cathode
(b)
Liquid sodium is obtained at the anode
(c)
The emf of the overall reaction is -4.07 V
(d)
Cl2 is released at the cathode and Liquid sodium is obtained at the anode
The metals near the bottom of the electro chemical series are ______.
(a)
strong reducing agents
(b)
strong oxidising agents
(c)
weak reducing agents
(d)
weak oxidising agents
Which one of the following characteristics are associated with adsorption?
(a)
\(\Delta\)G and \(\Delta\)H are negative but \(\Delta\)S is positive
(b)
\(\Delta\)G and \(\Delta\)S are negative but \(\Delta\)H is positive
(c)
\(\Delta\)G is negative but \(\Delta\)H and \(\Delta\)S are positive
(d)
\(\Delta\)G,\(\Delta\)H and \(\Delta\)S all are negative.
Which one of the following is correctly matched?
(a)
Emulsion - Smoke
(b)
Gel - butter
(c)
foam - Mist
(d)
whipped cream - sol
Which among the following does not affect adsorption?
(a)
surface area of the adsorbent
(b)
catalyst
(c)
temperature
(d)
pressure
An emulsion is a colloidal solution of _______.
(a)
two solids
(b)
two liquids
(c)
two gases
(d)
one solid and one liquid
Which of the following compound can be used as antifreeze in automobile rediators?
(a)
methanol
(b)
ethanol
(c)
Neopentyl alcohol
(d)
ethan -1, 2-diol
One mole of an organic compound (A) with the formula C3H8O reacts completely with two moles of HI to form X and Y. When Y is boiled with aqueous alkali it forms Z. Z answers the iodoform test. The compound (A) is ______.
(a)
propan – 2-ol
(b)
propan -1-ol
(c)
ethoxy ethane
(d)
methoxy ehane
Ethers in the presence of atmospheric oxygen oxidises to give hydroperoxides and dialkyl peroxides Such a spontaneous reaction by atmospheric oxygen is called ______.
(a)
auto oxidation
(b)
acylation
(c)
alkylation
(d)
dehydration
The characteristic odour of lower phenol is _________.
(a)
carbolic acid
(b)
fruity
(c)
oil of bitter almond
(d)
rotten fish
Phenyl methanal is reacted with concentrated NaOH to give two products X and Y. X reacts with metallic sodium to liberate hydrogen X and Y are ________.
(a)
sodium benzoate and phenol
(b)
Sodium benzoate and phenyl methanol
(c)
phenyl methanol and sodium benzoate
(d)
none of these
An alkene “A” on reaction with O3 and Zn - H2O gives propanone and ethanol in equimolar ratio. Addition of HCl to alkene “A” gives “B” as the major product. The structure of product “B” is ______.