Explore topic-wise InterviewSolutions in Current Affairs.

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1.

Which of the following is/are correct about the redox reaction? MnO_(4)^(ɵ)+S_(2)O_(3)^(2-)+H^(o+)toMn^(+2)+S_(4)O_(6)^(2-)

Answer»

1 " mol of "`S_(2)O_(3)^(2-)` is oxidised by 8 " mol of "`MnO_(4)^(ɵ)`
The above redox REACTION with the change of pH from 4 to 10 will have an effect on the stoichiometry of the reaction.
Change of pH form 4 to 7 will change the NATURE of the product.
At `pH=7,S_(2)O_(3)^(2-)` IONS are oxidised to `HSO_(4)^(ɵ)`

Solution :(a). `5e^(-)+MnO_(4)^(ɵ)toMn^(2+)(n=5)`
`2S_(2)O_(3)^(2-)toS_(4)O_(6)^(2-)+2e^(-)(n=(2)/(2)=1)`
" Eq of "`MnO_(4)^(ɵ)-=" Eq of "S_(2)O_(3)^(2-)`
`5xx` MOLES of `MnO_(4)^(ɵ)-=1xx` moles of `S_(2)O_(3)^(2-)`
`therefore` 1 " mol of "`S_(2)O_(3)^(2-)=5 " mol of "MnO_(4)^(ɵ)`
(b). pH changes from 4 to 10 (acidic to strongly basic)
`e^(-)+MnO_(4)^(ɵ)toMnO_(4)^(2-)(n=1)`
`S_(2)O_(3)^(2-)to2SO_(4)^(2-)+8e^(-)(n=8)`
" Eq of "`MnO_(4)^(ɵ)=" Eq of "S_(2)O_(3)^(2-)`
`therefore` 1 " mol of "`S_(2)O_(3)^(2-)=(1)/(8)" mol of "MnO_(4)^(ɵ)`
Hence with change of pH from 4 to 10, will change the stoichiometry of reaction and also changes the product.
(c). pH changes from 4 to 7 (acidic to neutral medium)
`3E^(-)+MnO_(4)^(ɵ)toMnO_(2)(n=3)`
`S_(2)O_(3)^(2-)to2HSO_(4)^(ɵ)+8e^(-)(n=8)`
Hence it will also effect the stoichiometry of reaction and natural of product.
(d). `At pH=7,S_(2)O_(3)^(2-)` is oxidised to `HSO_(4)^(ɵ)` ion.
Discussion
2.

Which of the following is a square planner ?

Answer»

`[NiCl_4[^(2-)`
`SF_4`
`XeF_4`
`[NI(CN)_4]^(2-)`

ANSWER :C
Discussion
3.

Which of the following is/are correct matchings ?

Answer»

`CH_(3)-OVERSET(C)overset(||)(C)-OH` and `H-overset(O)overset(||)(C)-OCH_(3)` -Metamers
`CH_(3)-CH_(2)-C-=CH` and `CH_(3)-C-=CH_(3)`-POSITION isomers
`CH_(3)CH_(2)CH_(2)NH_(2)` and `CH_(3)-underset(NH_(2))underset(|)(CH)-CH_(2)`-Tautomers
`CH_(3)CH_(2)OH` and `(CH_(3))_(2)O`-Functional isomer

Answer :B::D
Discussion
4.

The transition metal used as a catalyst is

Answer»

Nickel
Platinum
Cobalt
All of these

Solution :Ni, PT and Co all three TRANSITION metals are used as a CATALYSTS.
Discussion
5.

Which of the following is the coldest region ?

Answer»

Troposphere
Mesosphere
Stratosphere
Thermosphere

Answer :B
Discussion
6.

Which of the following order is /are incorrect ?

Answer»


SOLUTION :N/a
Discussion
7.

Which among the following is correct of ._(5)B in normal state?

Answer»


ANSWER :C
Discussion
8.

Writenoteon decomposition reaction .

Answer»


Answer :Decomposition reaction : REDOX REACTIONS in which a compound breaks down into two or more COMPONENTS are called decomposition reactions. These reactions are opposite to combination reactions. In these reactions , the oxidation number of the different ELEMENTS in the same substance is changed .
`(##SUR_CHE_XI_VO2_S_MQP_02_E01_053_A01##)`
Discussion
9.

Whichof these will not be oxidised by ozone

Answer»

KI
`FeSO_(4)`
`KMnO_(4)`
`K_(2)MnO_(4)`

Solution :`KMnO_(4)` cannot be oxidized further because Mn is ALREADY in its maximum OXIDATION STATE of +7
Discussion
10.

Whichwerethe majorproblemsbeforethescientistsafter the discoveryof subatomicparticles ?

Answer»

Solution :The majorproblems beforethe scientistsat thattimewere
to accountfor thestabilityof atom afterthediscoveryof SUBATOMIC particles . TOUNDERSTAND the orgin and nature of thecharacteristicsof ELECTROMAGNETICRADIATION absorbedor emitted by ATOMS.
Discussion
11.

You have the following substances :NH_(3),O_(2),andH_(2)O. Write equations for the preparation N_(2)O from these substances.

Answer»

SOLUTION :`4NH_(3)(G)+5O_(2)(g)UNDERSET(1100K)overset(Pt)to4NO(g)+6H_(2)O(l):""2NO(g)+O_(2)(g)to2NO_(2)(g)`
`3NO_(2)(g)+H_(2)O(l)to2HNO_(3)(aq)+NO(g),NH_(3)(g)+HNO_(3)(aq)toNH_(4)NO_(3)(aq)`
`NH_(4)NO_(3)(aq)underset("at room temperature")overset("Vacuum evaporation")toNH_(4)NO_(3)(s),""NH_(4)NO(s)overset(523K)toN_(2)O(g)+2H_(2)O(l)`
Discussion
12.

Write the possible metameric structure for C_4 H_(10) .

Answer»

SOLUTION :`C_4 H_(10)O `:
`underset("1- methyoxypropane ")((i)CH_3 -O-CH_2 -CH_3)`
`(ii )CH_3-O-underset( 2 "methoypropane ") underset(CH_3) underset( |)CH - CH_3`
` (iii )underset( "ethoxy ethane ")(CH_3-CH_2 -O- CH_2-CH_3)`
Discussion
13.

Which of the following does not illustrate the anomalous property of Li ?

Answer»

The m.p. and b.p. of LI are compara-tively high
Li forms a nitride `Li_(3)N` unlike group I metal
Li is much softer than the other I group METALS
`Li^(+)` ion is more heavily HYDRATED than those of the rest of the group 

Answer :C
Discussion
14.

The threshold frequency of a metal is 1.11 xx 10^(16) Hz. What is the maximum kinetic energy of the photo electron produced by applying a light of 15Å on the metal?

Answer»

Solution :`v=(C)/(lambda)=(3.0xx10^(8))/(15xx10^(-10)m)=2XX10^(17)Hz`
`KE=hv-hv_(0)`
`KE=[6.625xx10^(-34)Jsxx2xx10^(17)s^(-1)]-[6.625xx10^(-34)Jsxx1.11xx10^(16)s^(-1)]`
`"Kinetic ENERGY "=1.25xx10^(-16)J`
Discussion
15.

Which of the following is arranged in the increasing order of enthalpyof vaporisation ?

Answer»

`NH_(3). PH_(3). AsH_(3)`
`AsH_(3), PH_(3), NH_(3)`
`NH_(3) . AsH_(3),Ph_(3)`
`PH_(3), AsH_(3), NH_(3)`

ANSWER :D
Discussion
16.

When a saturated solution of KCL is heated it becomes

Answer»

UNSATURATED
supersaturated
remains saturated
ATTAINS EQUILIBRIUM

Answer :A
Discussion
17.

Which reagent will bring about the conversion of carboxylic acids into esters ?

Answer»

`C_(2)H_(5)OH`
Dry `HCl + C_(2)H_(5)OH`
`LiAlH_(4)`
`AL(OC_(2)H_(5))_(3)`

Solution :`RCOOH + C_(2)H_(5)OH underset(HCl)overset("dry")rarr RCOOC_(2)H_(5) + H_(2)O`
Discussion
18.

Which one is not in IUPAC system ?

Answer»

`underset(("3-methyl-2-butanol"))(CH_(3)-underset(OH)underset(|)(CH)-underset(CH_(3))underset(|)(CH)-CH_(3))`


SOLUTION :It should be `4-`ETHYL`-3-`methyl HEPTANE.
Discussion
19.

What is the average distance between covalent molecules of two atoms called ?

Answer»

ATOMIC RADIUS
Vaander Waal's
Covalent radius
IONIC radius

Answer :C
Discussion
20.

What is the correct order of decreasing stability of the following cations? underset(I)(CH_(3)-overset(+)(C)H-CH_(3))""underset(II)(CH_(3)-overset(+)(C)H-OCH_(3)) underset(III)(CH_(3)-overset(+)(C)H-CH_(2)-OCH_(3))

Answer»

IIgtIgtIII
IIgtIIIgtI
IIIgtIgtII
IgtIIgtIII

Solution :
THUS, the stabiloity of CARBOCATIONS DECREASES in the ORDER: IIgtIgtIII.
Discussion
21.

Which of the following is second most electronegative element ?

Answer»

CHLORINE
FLUORINE
OXYGEN
SULPHUR

ANSWER :A
Discussion
22.

Which of the following elements form peroxides when heated in excess of air ?

Answer»

K
NA
BA
Ca

Solution :K FORMS superoxide , `KO_(2)` while others FORM peroxides .
Discussion
23.

Washing soda is

Answer»

`Na_(2)CO_(3) . 7H_(2)O`
`Na_(2)CO_(3) . 10H_(2)O`
`Na_(2)CO_(3) . 3 H_(2)O`
`Na_(2)CO_(3)`

Answer :B
Discussion
24.

Which among the following statement(s) describe an element ? (i) It is pure substance which could be split into two or more simpler substance. (ii) It is a pure substance which cannot be split into simpler substance (iii) It's composition is not uniform (iv) All the above

Answer»

only (IV)
only (II)
(ii) and (III)
(i) and (iii)

Discussion
25.

What is meant by .demineralised. water and how can it be obtained ?

Answer»

Solution :Permanent hardness is due to the presence of soluble salts of magnesium and calcium in the form of chlorides and sulphates in water.
Permanent hardness is not REMOVED by BOILING. It can be removed by the following methods.
(i) Treatment with washing soda (sodium carbonate) : Washing soda reacts with soluble calcium and magnesium chlorides and sulphates in hard water to form insoluble CARBONATES.
`MCl_2 + Na_2CO_3 to MCO_3 darr + 2NaCl (M=Mg,Ca)`
`MSO_4 + Na_2CO_3 to MCO_3 darr + Na_2SO_4`
(ii) Calgon.s method: Sodium hexametaphosphate `(Na_6P_6O_18)` , commercially called .calgon., when added to hard water, the following reactions take place.
`Na_6P_6O_18 to 2Na^(+)+ Na_4 P_6O_18^(2-)`
`M^(2+) + Na_4P_6O_18^(2-) to [Na_2MP_6O_18]^(2-) + 2Na^(+)` (M=Mg, Ca)
The complex anion keeps the `Mg^(2+)` and `Ca^(2+)` ions in solution.
(iii) Ion-exchange method : This method is also called zeolite/permutit process. Hydrated sodium aluminium silicate is zeolite/permutit.
For the sake of simplicity, sodium aluminium silicate `(NaAlSiO_2)` can be written as NaZ. When this is added in hard water, exchange reactions take place.
`2NaZ_((s)) + M_((aq))^(2+) to MZ_(2+(aq)) to NZ_(2(s)) + 2Na_((aq))^(+)` (M=Mg, Ca)
Permutit/zeolite is said to be exhausted when all the sodium in it is used up. It is regenerated for further use by treating with an aqueous sodium chloride solution.
`MZ_(2(s)) + 2NaCl_((aq)) to 2NaZ_((s)) + MCl_(2(aq))`
(iv) Synthetic resins method : Nowadays hard water is softened by USING synthetic cation EXCHANGERS. This method is more efficient than zeolite process.
Cation exchange resins It contain large organic molecule with -`SO_3H` group and are water insoluble. Ion exchange resin `(RSO_3H)` is changed to RNa by treating it with NaCl.
The resin exchanges `Na^+` ions with `Ca^(2+)` and `Mg^(2+)` ions present in hard water to make the water soft. Here R is resin anion.
`2RNa_((s))+ M_((aq))^(2+) to R_2M_((s)) + 2Na_((aq))^(+)`
The resin can be regenerated by adding aqueous NaCl solution.
Pure de-mineralised (de-ionized) water free from all soluble mineral salts is obtained by passing water successively through a cation exchange in the `H^+` form) and an anion exchange in the `OH^-` form) resins.
`2RH_((s)) + M_((aq))^(2+) hArr MR_(2(s)) + 2H_((aq))^(+)`
In this cation exchange process, H+ exchanges for `Na^(+), Ca^(2+), Mg^(2+)` and other cations present in water.
This process results in proton release and thus makes the water acidic.
Anion exchange process :
`RNH_(2(s)) + H_2O_((l)) hArr RNH_(3)^(+) . OH_((s))^(-)`
`RNH_3^(+). OH_((s))^(-) + X_((aq))^(+) hArr RNH_(3)^(+) . X_((s))^(-) + OH_((aq))^(+)`
`OH^-` exchanges for anions like `Cl^(-), HCO_3^(-), SO_4^(2-)`etc. present in water. `OH^-` ions, thus, liberated neutralise the `H^+` ions set free in the cation exchange.
`H_((aq))^(+) + OH_((aq))^(-) to H_2O_((l))`
The exhausted cation and anion exchange resin beds are regenerated by treatment with dilute acid and alkali solutions respectively.
Discussion
26.

The strongest ionic bond is present in

Answer»

LIF
NAF
RBF
CSF

ANSWER :A
Discussion
27.

The wavelength of spectral line for electron transition is inversely related to

Answer»

NUCLEAR charge 
Velocity of ELECTRON 
NUMBER of electrons undergoing transition 
The energy DIFFERENCE between the energy LEVELS involving transition. 

Answer :D
Discussion
28.

Which of the following statement(s) is are not correct with reference to ferrous and ferric ions

Answer»

`Fe^(3+)` GIVES brown colour with POTASSIUM ferricynide
`Fe^(2+)` gives blue precipitate with potassium ferricyanide.
`Fe^(3+)` gives RED colour with potassium sulphocyanide
`Fe^(2+)` gives brown colour with potassium sulphocyanide.

Solution :`Fe^(3+)` produces red colouration with `KSCN` but `Fe^(2+)` does not give brown colour with KSCN.
Discussion
29.

Which of the following is a Bronsted-Lowry acid but not an Arrhenius acid?

Answer»

HCL
`NH_4^(+)`
`BF_3`
` CH_3COOH `

SOLUTION :`NH_4^(+) ` cannot DONATE`H^(+) `in WATER
Discussion
30.

Total number of molecules having three centered two e^(-) bonds among the following is B_(2)H_(6),Al_(2)Cl_(6),BeCl_(2)(S), BeH_(2)(S), Al_(2)H_(6), [Be_(2)(CH_(3))_(2)]n,C_(2)H_(6),Al_(2)(CH_(3))_(3),C_(2)(CH_(3))_(6)

Answer»


Solution :`B_(2)H_(6), BeH_(2)(S), Al_(2)H_(6), Al_(2)(CH_(3))_(3), [Be_(2)(CH_(3))_(2)]_(n)`
Discussion
31.

Three isotopes of an element have mass numbers m, (m + 1) and (m + 2). If the mean mass number is (m + 0.5) then which of the following ratios may be accepted for m,(m + 1) (m + 2) in that order?

Answer»

`1:1:1`
`4:1:1`
`3:2:1`
`2:1:1`

ANSWER :B
Discussion
32.

Which of the following is the most stable form of the mentioned compound?

Answer»

Eclipsed
Anti
Gauche
Skew

Solution :Due to attraction between `-OVERSET(o+)NMe_(3)`and `-overset(DELTA-)F` GROUP
Discussion
33.

The soliders of Napolean army while at Alps during freezingwinter suffereda serious problem as regards the tin buttongs of theiruniforms.White metallictin buttons got convertedinto grey powder. This transformationis related to

Answer»

an INTERACTIONWITH nitrogenof the air at very low temperatures
a change in the crystallines structure of tin.
a change iin the partial pressure of OXYGEN in the air.
an interaction with WATER vapour contained in the humid air.

Answer :B
Discussion
34.

The total number of isomers in C_(6)H_(3)Cl_(3)

Answer»

two
THREE
four
FIVE

Answer :B
Discussion
35.

Which one of the following sets of compounds correctly illustrate the law of of reciprocal proportions.

Answer»

`P_(2)O_(3), PH_(3), H_(2)O`
`P_(2)O_(5),PH_(3),H_(2)O`
`N_(2)O_(5), NH_(3), H_(2)O`
`N_(2)O, NH_(3), H_(2)O`

Answer :A::B::C
Discussion
36.

Write the expression for the equilibrium constant, K_c for each of the following reactions : (a)2NOCl(g) hArr 2NO(g)+Cl_2(g) (b)2Cu(NO_3)_2(s) hArr 2CuO(s) +4NO_2(g) (c )CH_3COOC_2H_5 hArr CH_3COOH(aq)+C_2H_5OH(aq) (d)Fe^(3+)(aq) +3OH^(-) (aq) hArr Fe(OH)_3(s) (e) I_2(s) + 5F_2(s) hArr 2IF_5(g)

Answer»

Solution :(a)`2NOCl(g) hArr 2NO(g)+Cl_2(g)`
`K_c=([NO]^2 [Cl_2])/([NOCl]^2)`
(b)`2Cu(NO_3)_2(s) hArr 2CuO(s) +4NO_2(g) +O_2(g)`
`K_c=[NO_2]^4[O_2]`
(c ) `CH_3COOC_2H_5(aq)+H_2O(L) hArr CH_3COOH(aq)+C_2H_5OH(aq)`
`K_c=([CH_3COOH][C_2H_5OH])/([CH_3COOC_2H_5])`
(d)`FE^(3+)(aq)+3OH^(-)(aq) hArr Fe(OH)_3(s)`
`K_c=1/([Fe^(3+)][OH^-]^3)`
(e) `I_2(s) + 5F_2(g) hArr 2IF_5(g)`
`K_c=([IF_5]^2)/([F_2]^5)`
Discussion
37.

Which of the following is the most suitable method for removing the traces of water from ethanol?

Answer»

REACTING with Na metal
Passing dry HCl through it
Distilling it
Reacting with MG

Solution :`Mg+C_(2)H_(5)OH rarr Mg(OC_(2)H_(5))_(2)+H_(2)`
`Mg(OC_(2)H_(5))_(2)+H_(2)O rarr MgO+2C_(2)H_(5)OH`.
Discussion
38.

This reaction is classified as

Answer»

Electrophilic substitution reaction
Free radical substitution reaction
Nucleophilic substitution reaction
Electrophilic ADDITION reaction

Answer :B
Discussion
39.

why are alkali metals strong reducing agents?

Answer»

SOLUTION :It is because of low IONISATION energy. They lose electrons EASILY, that is why they are STRONG reducing agents.
Discussion
40.

The structure of H_2O_2 is …..

Answer»

planar
non-planar
spherical
linear

Answer :B
Discussion
41.

What value are permitted for the angular momentum quantum number l for an electron with principal quantum number n = 4 ?

Answer»

SOLUTION :0, 1, 2, 3
Discussion
42.

When alpha- rays strike a thin gold foil then,

Answer»

most of the `alpha` - rays do not PASS through the GOLD FOIL.
most of the `alpha`- rays get DEFLECTED back.
most of the `alpha`-rays get deflected through small angles
most of the `alpha`- rays pass through WITHOUT any deviation.

Answer :D
Discussion
43.

When a light of frequency v_(1) is incident on a metal surface the photoelectrons emitted have twice the kinetic energy as did the photoelectron emitted when the same metal has irradiated with light of frequency v_(2). What will be the value of threshold frequency?

Answer»

`v_(0)=v_(1)-v_(2)`
`v_(0)=v_(1)-2v_(2)`
`v_(0)=2v_(1)-v_(2)`
`v_(0)=v_(1)+v_(2)`.

Answer :C
Discussion
44.

Write the possible isomers for the formula C_(5)H_(10) with their name and type of isomerism present in it.

Answer»

Solution :`C_(5)H_(10)`: (i) `CH_(3)-CH_(2)-CH_(2)–CH = CH_(2)` (Pent-1-ene)
(II) `CH_(3)-CH_(2)-CH=CH-CH_(3)` (Pent-2-ene)
The TYPE of isomerism present above is POSITION isomerism.
Discussion
45.

Which of the following does possess acidic character?(i) Butane (ii) But-1-ene (iii) But-1-yne (iv) But-2-yne

Answer»

SOLUTION :But-1-yne
Discussion
46.

Which of the following when dissolved in water forms a solution which is nonconducting ?

Answer»

Chile salt PETRE
Green vitrol
Potash ALUM
Alcohol

ANSWER :D
Discussion
47.

Which sets of quantumnumber are consitentwith the theory ?

Answer»

`n = 2,L = 1,m = 0,s = -1//2`
`n = 4,l = 3,m = -2,s = -1//2`
`n = 3,l = 2,m = -3,s = +1//2`
`n = 4,l = 3,m = -3,s = +1//2`

Solution :In `d,n = l i.e. , 3 but l = n`
Discussion
48.

When citric acid is heated at 525 K, the main product formed is

Answer»

Acetone
Aconitic acid
Ethanal
None of these

Solution :
Discussion
49.

Which of the following alkali metals forms only, the normal oxide , M_(2)O on heating in air ? (where M is the alkali metal).

Answer»

Rb
K
Li
Na

SOLUTION :Li FORMS only the NORMAL oxide , `Li_(2)O`.
Discussion
50.

VSEPR theory is used to predict the shape of covalent molecules.Based on VSEPR theory predict the shape of H_2O and NH_3

Answer»

SOLUTION :B REFER to TEXT
Discussion