Multiple Choice Questions

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The correct match of contents in Column I with those in Column II is

  Column I   Column II
(A) He (i) High electron affinity
(B) Cl (ii) Most electropositive element
(C) Ca (iii) Strongest reducing agent
(D) Li (iv) Highest ionisation energy
  • A-iv, B-i, C-ii, D-iii

  • A-iii, B-i, C-ii, D-iv

  • A-iv, B-iii, C-ii, D-i

  • A-ii, B-iv, C-i, D-iii


A.

A-iv, B-i, C-ii, D-iii

(i) For noble gases (eg, He), ionisation energy is highest due to their completely filled electronic configuration.

(ii) Generally electron affinity increases in a period (from IA to VII A group) and decreases in a group but electron affinity is highest for chlorine (Cl) (due to smaller size and high electron density of fluorine).

(iii) The ionisation energy is lowest for Li, so it can lose electrons very easily, thus it behaves as a strongest reducing agent.

(iv) Electropositive character generally decreases in a period (from left to right) and increases in a group (on moving down), thus Ca is the most electropositive element among the given.

Hence, on the basis of above facts, the correct matches are

(A)-iv (B)-i (C)-ii (D)-iii


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The lattice enthalpy and hydration enthalpy of four compounds are given below

Compound Lattice enthalpy (in kJ mol-1) Hydration
enthalpy
(in kJ mol-1)
P +780 -920
Q +1012 -812
R +828 -878
S +632 -600

The pair of compound which is soluble in water is

  • P and R

  • Q and R

  • P and Q

  • Rand S


In which one of the following pairs the radius of the second species is greater than that of the first?

  • Na, Mg

  • O2-, N3-

  • Li+, Be2+

  • Ba2+, Sr2+


The first () and second (ΔH2) ionisation enthalpies (in kJ mol-1) and the (ΔegH) electron gain enthalpy (in kJ mol-1) of the elements I, II, III, IV and V are given below

Element ΔH1 ΔH2 ΔegH
I 520 7300 -60
II 419 3051 -48
III 1681 3374 -328
IV 2372 5251 +48

The most reactive metal and the least reactive non-metal of these are respectively

 

  • I and IV

  • IV and II

  • II and IV

  • III and IV


The correct decreasing order of first ionisation enthalpies of five elements of the second period is

  • Be > B > C > N > F

  • N > F > C > B > Be

  • F > N > C > Be > B

  • N > F > B > C > Be


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The first ionisation energy of oxygen is less than that of nitrogen. Which of the following is the correct reason for this observation?

  • Lesser effective nuclear charge of oxygen than nitrogen.

  • Lesser atomic size of oxygen than nitrogen

  • Greater interelectron repulsion between two electrons in the same p-orbital counter balances the increase in effective nuclear charge on moving from nitrogen to oxygen.

  • Greater effective nuclear charge of oxygen than nitrogen.


The electronic configuration of the element with maximum electron affinity is

  • 1s2, 2s2,2p3

  • 1s2, 2s2,2p5

  • 1s2, 2s2,2p6, 3s2, 3p5

  • 1s2, 2s2,2p6, 3s2, 3p3


'Hydride Gap' is referred to which region of the Periodic Table ?

  • Groups 3, 4 and 5

  • Groups 5, 6 and 7

  • Groups 4, 5 and 6

  • Groups 7, 8 and 9


In which of the following the oxidation number of oxygen has been arranged in increasing order?

  • OF2 < KO2 < BaO2 < O3

  • BaO2 < KO2  < O< OF2 

  • BaO2  < O< OF2  < KO2 

  •  KO2  < OF2  < O< BaO2 


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The one electron species having ionization energy of 54.4 eV is :

  • H

  • He+

  • B4+

  • Li2+


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