Which one of the following methods can be used to obtain highly pure metal which is liquid at room temperature?
a.
Chromatography
b.
Distillation
Correct Answer
c.
Zone refining
d.
Electrolysis
Step-by-Step AI Explanation
Verified Method
Distillation is specifically used for the purification of metals which have low boiling points, such as Mercury (Hg), which is liquid at room temperature.
Q52mcq
The incorrect statement among the following is:
a.
Most of the trivalent Lanthanoid ions are colorless in the solid state.
Correct Answer
b.
Lanthanoids are good conductors of heat and electricity.
c.
Actinoids are highly reactive metals, especially when finely divided.
d.
Actinoid contraction is greater for element to element than Lanthanoid contraction.
Step-by-Step AI Explanation
Verified Method
Many trivalent Lanthanoid ions are colored due to f-f transitions. Statement (a) is incorrect as many are colored, not colorless.
Q54mcq
The correct sequence of bond enthalpy of ‘C–X’ bond is:
a.
CH3–F > CH3–Cl > CH3–Br > CH3–I
Correct Answer
b.
CH3–F < CH3–Cl > CH3–Br > CH3–I
c.
CH3–Cl > CH3–F > CH3–Br > CH3–I
d.
CH3–F < CH3–Cl < CH3–Br < CH3–I
Step-by-Step AI Explanation
Verified Method
Bond enthalpy decreases as the size of the halogen atom increases down the group, so C-F bond is strongest and C-I is weakest.
Q55mcq
Zr (Z=40) and Hf (Z=72) have similar atomic and ionic radii because of:
a.
diagonal relationship
b.
lanthanoid contraction
Correct Answer
c.
having similar chemical properties
d.
belonging to same group
Step-by-Step AI Explanation
Verified Method
Zr and Hf have similar radii due to lanthanoid contraction which offsets the expected increase in size down the group.
Q55mcq
Zr (Z=40) and Hf (Z=72) have similar atomic and ionic radii because of:
a.
diagonal relationship
b.
lanthanoid contraction
Correct Answer
c.
having similar chemical properties
d.
belonging to same group
Step-by-Step AI Explanation
Verified Method
Due to the filling of 4f orbitals in Lanthanoids, the shielding effect is poor, leading to Lanthanoid contraction, which offsets the increase in atomic size in the third transition series, making Zr and Hf sizes similar.
Q56mcq
A particular station of All India Radio, New Delhi, broadcasts on a frequency of 1,368 kHz (kilohertz). The wavelength of the electromagnetic radiation emitted by the transmitter is : [speed of light, c=3.0×10^8 ms^-1]
Which one of the following polymers is prepared by addition polymerisation?
a.
Nylon-66
b.
Novolac
c.
Dacron
d.
Teflon
Correct Answer
Step-by-Step AI Explanation
Verified Method
Teflon (polytetrafluoroethene) is an addition polymer, whereas Nylon-66, Novolac, and Dacron are condensation polymers.
Q58mcq
Which one of the following polymers is prepared by addition polymerisation?
a.
Nylon-66
b.
Novolac
c.
Dacron
d.
Teflon
Correct Answer
Step-by-Step AI Explanation
Verified Method
Teflon (polytetrafluoroethene) is formed by the addition polymerization of tetrafluoroethene. The others listed (Nylon, Novolac, Dacron) are condensation polymers.
Q59mcq
The compound which shows metamerism is:
a.
C3H8O
b.
C3H6O
c.
C4H10O
Correct Answer
d.
C5H12
Step-by-Step AI Explanation
Verified Method
Metamerism is exhibited by compounds having a polyvalent functional group like ether (C4H10O can be diethyl ether or methyl propyl ether).
Q60mcq
Among the following alkaline earth metal halides, one which is covalent and soluble in organic solvents is:
a.
Strontium chloride
b.
Magnesium chloride
c.
Beryllium chloride
Correct Answer
d.
Calcium chloride
Step-by-Step AI Explanation
Verified Method
Due to small size and high polarizing power, BeCl2 is covalent and soluble in organic solvents.
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The pKb of dimethylamine and pKa of acetic acid are 3.27 and 4.77 respectively at T (K). The correct option for the pH of dimethylammonium acetate solution is:
a.
5.50
b.
7.75
c.
6.25
d.
8.50
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The molar conductance of NaCl, HCl and CH3COONa at infinite dilution are 126.45, 426.16 and 91.0 S cm^2 mol^-1 respectively. The molar conductance of CH3COOH at infinite dilution is.
a.
390.71 S cm^2 mol^-1
b.
698.28 S cm^2 mol^-1
c.
540.48 S cm^2 mol^-1
d.
201.28 S cm^2 mol^-1
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The following solutions were prepared by dissolving 10 g of glucose (C6H12O6) in 250 ml of water (P1), 10 g of urea (CH4N2O) in 250 ml of water (P2) and 10 g of sucrose (C12H22O11) in 250 ml of water (P3). The right option for the decreasing order of osmotic pressure of these solutions is:
a.
P1 > P2 > P3
b.
P2 > P3 > P1
c.
P3 > P1 > P2
d.
P2 > P1 > P3
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Statement I: Acid strength increases in the order given as HF << HCl << HBr << HI. Statement II: As the size of the elements F, Cl, Br, I increases down the group, the bond strength of HF, HCl, HBr and HI decreases and so the acid strength increases.
a.
Both Statement I and Statement II are false.
b.
Statement I is correct but Statement II is false.
c.
Statement I is incorrect but Statement II is true.
d.
Both Statement I and Statement II are true.
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An organic compound contains 78% (by wt.) carbon and remaining percentage of hydrogen. The right option for the empirical formula of this compound is: [Atomic wt. of C is 12, H is 1]
a.
CH2
b.
CH3
c.
CH4
d.
CH
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The slope of Arrhenius Plot (ln k v/s 1/T) of a first order reaction is −5×10^3 K. The value of Ea of the reaction is. Choose the correct option for your answer. [Given R=8.314 J K−1 mol−1]
a.
83.0 kJ mol−1
b.
166 kJ mol−1
c.
-83 kJ mol−1
d.
41.5 kJ mol−1
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The correct option for the value of vapour pressure of a solution at 45°C with benzene to octane in molar ratio 3 : 2 is: [At 45°C vapour pressure of benzene is 280 mm Hg and that of octane is 420 mm Hg. Assume Ideal gas]
a.
168 mm of Hg
b.
336 mm of Hg
c.
350 mm of Hg
d.
160 mm of Hg
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The molar conductivity of 0.007 M acetic acid is 20 S cm² mol⁻¹. What is the dissociation constant of acetic acid? Given Λ°_H+ = 350 S cm² mol⁻¹, Λ°_CH3COO- = 50 S cm² mol⁻¹.
a.
2.50×10⁻⁴ mol L⁻¹
b.
1.75×10⁻⁵ mol L⁻¹
c.
2.50×10⁻⁵ mol L⁻¹
d.
1.75×10⁻⁴ mol L⁻¹
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Match List - I with List - II: (a) [Fe(CN)6]³⁻, (b) [Fe(H2O)6]³⁺, (c) [Fe(CN)6]⁴⁻, (d) [Fe(H2O)6]²⁺. List - II: Magnetic moments in BM: (i) 5.92, (ii) 0, (iii) 4.90, (iv) 1.73.
a.
(a)-(ii), (b)-(iv), (c)-(iii), (d)-(i)
b.
(a)-(i), (b)-(iii), (c)-(iv), (d)-(ii)
c.
(a)-(iv), (b)-(i), (c)-(ii), (d)-(iii)
d.
(a)-(iv), (b)-(ii), (c)-(i), (d)-(iii)
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Following are the statements with reference to ‘lipids’. (a) Lipids having only single bonds are called unsaturated fatty acids. (b) Lecithin is a phospholipid. (c) Trihydroxy propane is glycerol. (d) Palmitic acid has 20 carbon atoms including carboxyl carbon. (e) Arachidonic acid has 16 carbon atoms. Choose the correct answer from the options given below.
a.
(c) and (d) only
b.
(b) and (c) only
c.
(b) and (e) only
d.
(a) and (b) only
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