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1.

Volume of air that will be expelled from a vessel of 300 cm3 when it is heated from 27oC to 37oC at the same pressure will be a) 310 cm3 b) 290 cm3 c) 10 cm3 d) 37 cm3

Answer»

The correct option is (c) 10 cm3.

Explanation:

V1/T1 = V2/T2

V2 = V1T2/T1 = (300 x 310)/300 = 310 cm3

Volume of air expelled = 310 cm3 - 300 cm3 = 10 cm3

2.

Compounds that formally contain Pb4+ are easily reduced to Pb2+. The stability of the lower oxidation state is due to .......

Answer»

Compounds that formally contain Pb4+ are easily reduced to Pb2+The stability of the lower oxidation state is due to  Inert pair effect.

3.

Atomic radii of fluorine and neon in Angstrom units are respectively given by(a) 0.72,1.60(b) 1.60, 1.60(c) 0.72,0.72(d) None of these

Answer»

Correct option (a) 0.72,1.60

Explanation:

Atomic size of fluorine is its covalent radius, while the atomic size of neon is its van der Waals' radius.

4.

The first ionisation potential in electron volts of nitrogen and oxygen atoms are respectively given by(a) 14.6, 13.6 (b) 13.6. 14.6(c) 13.6, 13.6(d) 14.6, 14.6 

Answer»

Correct option (a) 14.6, 13.6 

Explanation:

The first ionisation potential of l{ > O because of extra stability gained by half-filled  p-orbitals of N.

N7 = 1s2, 2s2, 2p1x, 2py1 , 2p1z

O8 = 1s2, 2s2, 2p2x, 2py1 , 2p1z

5.

The first ionisation potential of nitrogen and oxygen atoms are related as follows(a) The ionisation potential of oxygen is less than the ionisation potential of nitrogen(b) The ionisatioir-potential of nitrogen is greater than the ionisation potential of oxygen(c) The two ionisation potential values are comparable.(d) The difference between the two ionisation potential is too large.

Answer»

Correct option (a)(b)(c)

Explanation:

N7 = 1s2,2s2p3

O8 =  1s2, 2s2 2p4

Half-filled or completely filled orbitals are more stable.

Hence. IE of oxygen is less than that of nitrogen.

6.

The element with the highest first ionisation potential is(a) boron (b) carbon(c) nitrogen(d) oxygen

Answer»

Correct option (c) nitrogen

Explanation:

Generally first ionisation potential increases from left to right in a period but first ionisation potential of nitrogen is greater than that of oxyen due to presence of half-filled 2p orbitals in nitrogen.

7.

On Mulliken scale, the average of ionisation potential and electron affinity is known as ...................

Answer»

On Mulliken scale, the average of ionisation potential and electron affinity is known as electronegativity.

8.

The decreasing order of electron affinity of F, Cl, Br is F>Cl>Br

Answer»

False : Order of electron affinity Cl > F > Br because the size of F-atom is lower than that of Cl- atom, so the electron density on the surface of F is higher than that of chlorine. Thus, during the addition of an additional electron. higher repulsion takes place in fluorine than chlorine.

So, more amount of energy is consumed for the accommodation of addition electron in fluorine than chlorine. Hence, not released a large amount of energy.

This energy is higher in chlorine than fluorine ie, electron affinity of F<Cl.

Bromine shows lower electron affinity than F and Cl due to its larger size. 

9.

Arrange the following in the order of their increasing size :Cl-,S2-,Ca2+,Ar

Answer»

Increasing order of size

Ca2+ < Ar < ClS2-

Radii ∝ 1/effective nuclear charge

10.

Let P(x) = F(x)G(x) and Q(x) = F(x)/G(x), where F and G are the functions whose graphs are shown.(a) Find P ’ (2)(b) Find Q ’ (7)The graph for this problem is on page 188, I’m sorry I could not copy it on this. Please help me step by step.

Answer»

Answer:

(a) P’(2) will be the derivative of P(x) evaluated at x=2. So first, we take a derivative.
In this section, you should have learned product rule, so P’(x) will look like this:
P’(x)=F(x)G’(x)+F’(x)G(x)

Now we let x=2.
P’(2)=F(2)G’(2)+F’(2)G(2)

Read these values off the graph.
We see that F(2)=3. (When its x-value is 2, the curve F has a y-value of 3)
We see that G(2)=2.
F’(2) will be the slope of the curve F at 2. A tangent line at F(2) would be horizontal, so F’(2)=0.
G(2) has a slope of 1/2, so G’(2)=1/2

Now we substitute these values into P’(2) to solve:

P’(2)=(3)(1/2)+(0)(2)=(3/2)+(0)=3/2

(b) We’re playing by the same rules as above–differentiate the equation, read the values off the graph, substitute the values into the function, and solve.

Differentiate (Quotient Rule):
Q’(x)=[G(x)F’(x)-F(x)G’(x)]/[G(x)2]
Read the values off the graph:
G(7)=1
G’(7)=-2/3
F(7)=5
F’(7)=1/4
Substitute:
Q’(7)=[1*(1/4)-5*(-2/3)]/[12]
Q’(7)=[(1/4)+(10/3)]
Q’(7)=(43/12)=3.5833.

11.

a regular hexagon and a regular dodecagon are inscribed in a same circle if the side of a dodecagon is ✓3-1 then the side of hexagon is

Answer»

I hope it would help you to get the answer!!!

We have, for dodecagon sin(2π/40) = (a/2)/r     

so, r = (a/2)/ sin(π/20)

and for hexagon sin(2π/12) = (x/2)/r       

so, x/2 = r sin(π/6)  =  (a/2) sin(π/6)/ sin(π/20)  

Now solve for x, you'll get the answer.

12.

If the point (a,a) lie between the lines |x+y|=2, then which of the following is correct ? (i) |a|=2(ii) |a|=1(iii) |a|&lt;1(iv) |a|&lt;1/2

Answer»

|a|<1

Option (iii) is the correct answer.

13.

How we calculate n factor for dispropornation reaction

Answer»

You can calculate n factor in disproportionation reaction by the formula

 1/N=1/n1 +1/n2

where n1=n factor for oxidation half  and n2=n factor for reduction half

As example:
I→ IO3- + I
Now we calculate n1 -
The oxidation reaction is I→ 2IO3− + 10e
n1= 10
Now we calculate n
The reduction reaction is - 2e− + I→ 2I
n2 = 2
Hence , n = 5/3

14.

दो ध्वनि तरंगे जिनमे कलांतर `90^(@)` है में पथांतर क्या होगा -A. `lamda/6`B. `lamda/3`C. `lamda/4`D. इनमे से कोई नहीं

Answer» Correct Answer - A
15.

दोनों सिरे से तनी डोरी मे किस प्रकार की संनादी उत्पन्न होती है-A. समB. विषमC.दोनोंD. इनमे से कोई नहीं

Answer» Correct Answer - C
16.

दो ध्वनि स्रोत्र स्वरमेल में है। प्रति सेकंड कितने विस्पंद सुनाई देंगे-A. एकB. तीनC. शून्यD. इनमे से कोई नहीं

Answer» Correct Answer - C
17.

प्लेटफॉर्म पर खड़ा रेलगाड़ी की सीटी की आवृत्ति स्थिर हवा में 400 हर्ट्ज है। एक व्यक्ति को सीटी की आवृत्ति कितनी प्रतीत होगी -यदि व्यक्ति इंजन की और 10 मीटर /सेकंड की चाल से दौड़ रहा हो -A. 412 HZB. 512HZC. 314HZD. 200HZ

Answer» Correct Answer - A
18.

एक गतिमान श्रोता को स्थिर ध्वनि - स्रोत्र दूर किस वेग से जाना चाहिए की उसे ध्वनि ध्वनि का तारत्व 20 प्रतिशत गिरा हुआ प्रतीत हो ? ध्वनि का वेग 330 मीटर/सेकंड है-A. 12m/sB. 66 m/sC. 34m/sD. 61m/s

Answer» Correct Answer - B
19.

एक कार के टायर में `27^@` पर भरी वायु का दाब 3 वायुमंडलीय है। यदि वायु का ताप `47^@` हो जाये तो टायर के अंदर दाब कितना हो जाएगा-A. 3.2वायुमंडलीयB. 4.2वायुमंडलीयC. 5.3वायुमंडलीयD. 6वायुमंडलीय

Answer» Correct Answer - A
20.

किसी वस्तु का न्यूनतम संभव ताप कितना हो सकता है -A. `273^(@)C`B. `266^(@)C`C. `253^(@)C`D. इनमे से कोई नहीं

Answer» Correct Answer - A
21.

गैसोंके अणुओ का वह गुण बताइये जो नियत ताप पर सभी गैसों के लिए समान रहता है -A. आयतनB. दाबC. तापD. गतिज ऊर्जा

Answer» Correct Answer - D
22.

एक गैस के चार अणुओ के वेग क्रमशः 2,4,6 और 8km/s है, तो वर्ग माध्य मूल वेग होगी-A. 5km/sB. 5.48km/sC. 7km/sD. 2km/s

Answer» Correct Answer - B
23.

गैस अणुओ कि माध्य गतिज ऊर्जा गैस कि प्रवृत्ति पर निर्भर करती है-A. सत्यB. असत्यC. कुछ कहा नहीं जा सकताD. इनमे से कोई नहीं

Answer» Correct Answer - D
24.

Consider the following hydrolysis reaction of a pure enantiomer of amide,The correct statement regarding the above hydrolysis reaction is/areA) Both acid and base can act as catalystB) In both acid and base catalysed condition, a pure enantiomer of amine withretention of configuration is obtainedC) Base catalysed hydrolysis is bimolecular while acid catalysed is unimolecularD) Base catalysed hydrolysis is unimolecular while acid catalysed is bimolecular

Answer»

Answer: A,B

Amides can be hydrolysed in both acidic medium. During hydrolysis of amides, alkylnitrogen bond is not dissociated, hence configuration at a-carbon of amine is retained.

25.

Ca2+ has a smaller ionic radius than K+ because it has ......

Answer»

Ca2+ has a smaller ionic radius than K+ because it has Higher effective nuclear charge

26.

The energy released when an electron is added to a neutral gaseous atom is called ...... of the atom.

Answer»

The energy released when an electron is added to a neutral gaseous atom is called Electron affinity of the atom.

27.

1)DO TlCl3  exist in nature?if not, give reason.2)DO PbCl4  exist in nature?if not, give reason

Answer»

Its look like your question is not complete please post your complete question..............

28.

The statement that is not correct for the periodic classification of elements, is(a) The properties of elements are the periodic functions of their atomic numbers. (b) Non-metallic elements are lesser in number than metallic elements.(c) The first ionisation energies of elements along a period do not very in a regular manner with increase in atomic number.(d) For transition elements the d-subshells are tilled with electrons monotonically with increase in atomic number.

Answer»

Correct option (d) For transition elements the d-subshells are tilled with electrons monotonically with increase in atomic number.

Explanation:

Among transition elements. electrons are not filled in d-subshell monotonically with increasing atomic number.

29.

Amongst the following elements (whose electronic configurations are given below), the one having the highest ionisation energy is(a) [Ne] 3s2 3p1(b) [Ne] 3s2 3p3(c)  [Ne] 3s2 3p2(d)  [Ar] 3d10 4s2 4s2 4p3

Answer»

Correct option (b) [Ne] 3s2 3p3

Explanation:

Ionisation energy increases with increasing atomic number in a period. while decreases on moving down the group.

30.

Which one of the following is the smallest in size ?(a) N3-(b) O2-(c) F-(d) Na+

Answer»

Correct option (d) Na+ 

Explanation:

For isoelectronic ions

ionic size ∝ 1/atomic number

31.

The first ionisation potential of Na, Mg, Al and Si are in the order(a) Na &lt;Mg&gt;AI&lt; Si(b) Na &gt; Mg &gt; AI&gt;Si(c) Na&lt; Mg&lt;AI&gt;Si(d) Na &gt; Mg &gt; Al&lt;Si

Answer»

Correct option (a) Na <Mg>AI< Si

Explanation:

First ionisation potential increases from left to right across a period but Mg has extra stability than Al, due to full-filled 3s -orbitals.

Na11  = 1s2,2s2,2p6,3s1

Mg12  = 1s2,2s2,2p6,3s2

AI13  =  1s2,2s2,2p6,3s2, 3p1

Si14  = 1s2,2s2,2p6,3s2, 3p2

Thus, correct order of first ionisation potential is :

Na<Mg>AL<Si

32.

The number of elements in the set { (a,b): 2a2 + 3b2 = 35 , a,b belongs to Z } where X is set of all integers isa) 2         b) 4c) 8        d) 12

Answer»

The possible sets are {±2 ,± 3} and {±4, ±1};

Therefore, number of elements in the required set is 8.