Explore topic-wise InterviewSolutions in Current Affairs.

This section includes 7 InterviewSolutions, each offering curated multiple-choice questions to sharpen your Current Affairs knowledge and support exam preparation. Choose a topic below to get started.

1.

Chemical reactions are invariably associated with the transfter of energy either in the form of heat or light. In the laboratory, heat changes in physical and chemical processes are measured with an instrument called calorimeter. Heat change in the process is calculated as {:(q = ms DeltaT,,s ="Specific heat"),(=cDeltaT,,c ="Heat capacity"):} Heat of reaction at constant volume is measured using bomb calorimeter. q_(V) = DeltaU = Internal energy change Heat of reaction at constant pressure is measured using simple or water calorimeter. q_(p)= DeltaH q_(p) = q_(V) +P DeltaV DeltaH = DeltaU +DeltanRT What value of DeltaT should be used for the calorimetry experiment that gives the following graphical results?

Answer»

`30^(@)C`
`45^(@)C`
`20^(@)C`
`35^(@)C`

SOLUTION :`DeltaH = DeltaU +DeltanRT`, where `Deltan =` change in number of MOLES. Hence, in given REACTION, `Deltan = 0`.
`:. DeltaH = DeltaU`
Discussion
2.

Chemical oxygen demand is determined by using

Answer»

Methylorgane
`K_(2) Cr_(2) O_(7) + 50% H_(2) SO_(4)`
`CaOCI_(2) + 50% H_(2) SO_(4)`
Alum + CaO

Answer :B
Discussion
3.

Chemical formula of lithium borohydride is

Answer»

`LIBH`
`LiBH_(2)`
`LiBH_(3)`
`LiBH_(4)`

ANSWER :D
Discussion
4.

Chemical equilibrium is dynamic. Justify.

Answer»

SOLUTION :Chemical equilibrium is dynamic : because the velocities of forward and backward reactions are equal, as ALSO the concentration of reactant and PRODUCT remain unchanged at this equilibrium state. (But may not be equal). The equilibrium can be made to shift in either direction by CHANGING the concentration, Pressure, or Volume. Hence it is dynamic in nature.
Discussion
5.

Chemical equilibrium is attained in a reversible reaction carried in a close container and is of dynamic nature. The value of equilibrium constant may be expressed either as K_(p)" and " K_(c) and the two are related to each other as : K_(p) =K_(c)(RT)^(Deltang) Free energy change (DeltaG) at equilibrium point is zero. The value of equilibrium constant gives the extent to which a particular reation has proceeded to attain the equilibrium . Its value gets reversed if the reaction is reversed and becomes the square root of the initial value if the reaction is divided by 2. For the reaction PCI_(3)(g)+ CI_(2) (s) hArr PCI_(5) (g) The value of k_(c) " at " 250^(@)C " is " " mol"^(-1) L^(-1). The value of k_(p) at the same temperaturewill be :

Answer»

<P>`0.61 ATM^(-1)`
`0.56 atm^(-1)`
`0.83 atm^(-1)`
`0.46 atm^(-1)`

Solution :`K_(p) =K_(c)(RT)^(Deltang) =(26 "mol" L^(-1))`
`x (0.0821 L atm K^(-1) mol^(-1) XX 523 K^(-1))`
`= 0.61 K`
Discussion
6.

Chemical equilibrium is attained in a reversible reaction carried in a close container and is of dynamic nature. The value of equilibrium constant may be expressed either as K_(p)" and " K_(c) and the two are related to each other as : K_(p) =K_(c)(RT)^(Deltang) Free energy change (DeltaG) at equilibrium point is zero. The value of equilibrium constant gives the extent to which a particular reation has proceeded to attain the equilibrium . Its value gets reversed if the reaction is reversed and becomes the square root of the initial value if the reaction is divided by 2. A reaction attains equilibrium when the free energy change accompanying the reaction is :

Answer»

POSITIVE and large
ZERO
Negative
Negative and small.

Solution :`DeltaG=0` when the reaction is in a STATE of EQUILIBRIUM
Discussion
7.

Chemical equilibrium, explain by example of 'chemical reaction'.

Answer»

Solution :(A) Example of Synthesis of ammonia : The chemical equilibrium can be demonstrated in the synthesis of ammonia by Haber.s process. In a series of experiments , Haber started with known amounts of dinitrogen and dihydrogen maintained at high temperature and PRESSURE and at REGULAR intervals determined the amount of ammoniapresent . He was successful in determining also the concentration of unreacted dihydrogen and dinitrogen .It is shown in following figure.

(B) Example of decomposition of hydrogen iodide (HI) : If we start with equal initial concentration of `H_2` and `I_2` the reaction proceeds in the forward direction and the concentration of `H_2` and `I_2` decreases while that of HI increases until. After some time concentration of all (of `H_2 ,I_2`, HI) become constant and it reach to equilibrium .
`H_(2(g)) + I_(2(g)) hArr 2HI_((g))` ...(iii)
At the same temperature we can take only HI and make the reaction to proceed in the reverse direction, the concentration of HI will decrease and of `H_2` and `I_2` will INCREASE. After some time concentration of all `(H_2, I_2, H_1)` will reach constant and equilibrium SITUATION formed.
`2HI_((g)) hArr H_(2(g)) + I_(2(g))`...(iv)
"Equilibrium can attain from any of the side while reaction."

In starting, `H_2` and `I_2` are reactant not products. At equilibrium all are components.
If in forward and backward reaction at definite temperature he no. of atoms H and I in constant volume be same then both will give equilibrium mixture.
Discussion
8.

Chemical equation is balanced according to the law ofmultiple proportionsreciprocal proportionsconservation of massdefinite proportions.

Answer»

MULTIPLE PROPORTIONS
RECIPROCAL proportions
conservation of mass
definite proportions.

Answer :C
Discussion
9.

Composition of PAN is

Answer»

`CH_(2)=CH-CHO`
`CH_(3)-UNDERSET(O)underset(||)(C)-O-O-NO_2`
`HCHO`
`CH_3CH_2ONO`

ANSWER :B
Discussion
10.

Chemical analysis of a carbon compound gave the following percentage composition by weight of the elements present, carbon = 10.06%, hydrogen = 0.84%, chlorine = 89.10%. Calculate the empirical formula of the compound.

Answer»

SOLUTION :`(CHCl_(3))`
Discussion
11.

Chemical A is used for water softening to remove temporary hardness. A reacts with sodium carbonate to generate caustic soda. When CO_(2) is bubbled through a solution of A, it turns cloudy. What is the chemical formula of A ?

Answer»

`CaCO_(3)`
`CaO `
`Ca(OH)_(2)`
`Ca(HCO_(3))_(2)`

Solution :`underset("TEMP. HARDNESS")(Ca(HCO_(3))_(2)) +Ca(OH)_(2) to underset(A)(2CaCO_(3))darr +2H_(2)O`
`underset((A))(Ca(OH)_(2)) +Na_(2) CO_(3) to underset("Caustic SODA")(CaCO_(3) darr )+ CaCO_(3)`
`underset(A)(Ca(OH)_(2)) + CO_(2) to underset("Milkiness")(CaCO_(3)) darr +H_(2)O`
Discussion
12.

CH=C-CH_(3)+H_(2)overset(pt)rarr?overset(H_(2)rarr

Answer»

Solution :`CH=C-underset("PROPYNE")(CH )_(3)+H_(2) OVERSET(2T)(to)CH_(2)= underset("Propene") (CH ) = CH_(3)overset(H_(2)pt)(to) CH_(3)= CH_(3) CH_(3)`
Discussion
13.

Charle's law may be expressed as

Answer»

<P>`(dV//dT)_(P) = K`
`(dV//dT)_(P) =KT`
`(dV//dT_(P) = - K//T^(2)`
`V = KT`

SOLUTION :ACCORDING to Charle's law, at constant pressure
`V PROP T` or `V=KT`
`(dV//dT)_(P)=K`
Discussion
14.

Charge of electron is

Answer»

`1,602xx10^(-10)" COULOMB"`
`4.8xx10^(-10)" Coulomb"`
`1.602xx10^(-19)" e.s.u"` 
`4.8xx10^(-10)" e.s.u"`

ANSWER :D
Discussion
15.

Charcoal possesses adsorption property, because

Answer»

it is a non-CONDUCTOR of electricity.
it is a conductor of electricity.
it is POROUS.
it is amorphous.

Answer :C
Discussion
16.

Characteristic reaction of alkenes is

Answer»

ELECTROPHILIC ADDITION
Nucleophiclic addition
Electrophilic SUBSTITUTION
NUCLEOPHILIC substitution

Answer :A
Discussion
17.

Char Coal is a ___________ element.

Answer»

ACID -making
Base -making
Salf - making
Neutral

Answer :a
Discussion
18.

Changes in a system from an initial state to the final state were made by a different manner that DeltaH remains same but q changes because

Answer»

`DELTAH` is a path function but q is astate function
`DeltaH` is a state functionand q is a path function
Both `DeltaH` ANDQ are state function
Both `DeltaH` and q are path function

Solution :As `DeltaH` REMAINS same by different paths,itisa state function. As q changes by different paths, it is a path function.
Discussion
19.

Change in internal energy, when 4 kJ of work is done on the system and 1 kJ of heat is givenout by the system is____

Answer»

`+1` KJ
`-5` kJ
`+3` kJ
`-3` kJ

Solution :`DELTAU=q+w`
`DeltaU`=-1 kJ+ 4 kJ
`DeltaU` =+3 kJ
Discussion
20.

Changein Gibbs free energy is given by _____

Answer»

SOLUTION :`DeltaG=DeltaH-TDeltaS`
Discussion
21.

Change in heat at constant volume (q_(v))=…......

Answer»

`Delta U `
`Delta H`
`RT`
`Delta G`

Answer :A
Discussion
22.

Change in entropy for one mole water from liquid from to vapour at 373 K is ........... Joule/ Kelvin.(Delta H_("vap") = 2.257 "KJ/gm")

Answer»

`105.9`
`107.9`
`108.9`
`109.9`

SOLUTION :`DELTA S= (Delta )/( T) = (18 XX 2257)/( 373) = 108.9`
Discussion
23.

Change in entropy during adsorption of gas on the solid substance is.......... .

Answer»

Increasing
decreasing
constant
infinite

Answer :B
Discussion
24.

Change in entropy for the expansion of 1 mole ideal gas in vacuum is ..........

Answer»

1 Joule
2 Joule
10 Joule
Zero

Answer :D
Discussion
25.

Change in enthalpy when 11.2 dm^3 of He at NTP is heated in a cylinder to 100^@C is

Answer»

623.5J 
1039J
1227J
520J 

ANSWER :B
Discussion
26.

Change in enthalpy during neutralization reaction of one mole HCI with dilute KOH at 298 K is .......... KJ

Answer»

`68`
`56`
`50`
`65`

ANSWER :B
Discussion
27.

Change in enthalpy is

Answer»

Heat ABSORBED at constant pressure
The total energy CHANGE at constant pressure and TEMPERATURE
EQUAL to change in internal energy at constant volume
All the above

Answer :A
Discussion
28.

Change in enthalpy and change in internal energy are state functions. The value of DeltaH, DeltaU can be determined by using Kirchoff's equation. Calculate the heat of formation of methane, given that heat of formation of water = -286kJ mol^(-1), heat of combustion of methane = -890kJ mol^(-1) heat of combustion of carbon = -393.5 kJ mol^(-1)

Answer»

`90.5 kJ mol^(-1)`
`-240 kJ mol^(-1)`
`-75.5 kJ mol^(-1)`
`95.6 kJ mol^(-1)`

Solution :`CH_(4) + 2O_(2) rarr CO_(2) + 2H_(2)O`
`DELTA H = Delta H_(f_(CO_(2))) + 2DELTA H_(f_(H_(2)O)) - Delta H_(f_(CH_(4)))`
`Delta H_("COMBUSTION"_(CH_(4))) = Delta H_("combustion"_(( C))) + 2 Delta H_(f_(H_(2)O)) - Delta H_(f_(CH_(4)))`
`-890 = -393.5 + 2 XX (-286) - Delta H_(f_(CH_(4)))`
`Delta H_(f_(CH_(4))) = - 75.5` kJ/mol
Discussion
29.

Change in enthalpy and change in internal energy are state functions. The value of DeltaH, DeltaU can be determined by using Kirchoff's equation. Calculate DeltaH when 10dm^(3) of helium at NTP is heated in a cylinder to 100^(@)C, assuming that the gas behave ideally.

Answer»

927.9J
279.2J
729.3J
999J

Solution :`Delta H = nC_(p)DT = ((10)/(22.4)) xx (5)/(2) xx 8.314 xx 100` = 927.9
Discussion
30.

Chain isomer of cyclobutene is

Answer»

`CH_(3)CH_(2)CH=CH_(2)`
`CH_(3)CH_(2)CH=CH-CH_(3)`

`CH_(3)-UNDERSET(CH_(3))underset(|)C=CH_(2)`

SOLUTION :
are chain ISOMERS because there is a differ in the carbon chain.
Discussion
31.

Chain-growth polymerization may proceed by the following mechanism:

Answer»

free RADICAL POLYMERIZATION
CATIONIC polymerization
ANIONIC polymerization
all of the above

Answer :D
Discussion
32.

Chain growth addition polymerization is an important reaction of:

Answer»

ALKENES
CONJUGATED DIENES
POLYSTYRENE
natural

Answer :A::B
Discussion
33.

Chadwick got the Nobel Prize for the discovery of _________.

Answer»

protons
neutrons
electrons
mesons

Answer :B
Discussion
34.

CH_(4(g))+2O_(2(g))hArrCO_(2(g))+2H_(2)O_((l)) DeltaH=-170.8" kJ mol"^(-1) which of the following statement is not true ?

Answer»

At equilibrium, the concentration of `CO_(2(g))` and `H_(2)O_((l))` are not equal
The equilibrium CONSTANT for the reaction is given by `K_(p)=([CO_(2)])/([CH_(4)][O_(2)])`
Addition of `CH_(4(g))` or `O_(2(g))` at equilibrium will CAUSE a shift to the right.
The reaction is exothermic.

ANSWER :B
Discussion
35.

CH_(4(g)) + 2O_(2(g)) rarr CO_(2(g)) + 2H_2O_((l)) DeltaH = -200 K.cal, now DeltaE Cal, now DeltaE for the same process at 300 K (in K.Cal)

Answer»

`-199.8`
`-198.9`
`-190.8`
`-198.8`

ANSWER :D
Discussion
36.

CH_(4) is not obtained by

Answer»

WURTZ reaction
Corey-house synthesis
Reduction of alkylhalide
Kolbe's electrolysis

Answer :A::B::D
Discussion
37.

CH_4is formed when

Answer»

SODIUM acetate is heated with SODA lime
iodomethane is reduced
aluminium CARBIDE reacts with WATER
all of the above.

Answer :D
Discussion
38.

CH_(4) gas is behaving non-ideally. Compressibility factor for gas is 1.5 at 2 atm, 400K. Calculate molar volume for gas: [Given: R=0.08("Litre"-"atm")/(K-"mole")]

Answer»

24 litre
16 litre
48 litre
8 litre

Answer :a
Discussion
39.

CH_4 diffuses two times faster than a gas X. The number of molecules present in 32 g of gas X is (N is Avogadro number)

Answer»

`N`
`N/2`
`N/4`
`N/16`

ANSWER :B
Discussion
40.

CH_4 + Cl_2 overset(hv)to CH_3 Cl + HCl to obtain high yields of CH_3Cl , the ratio of CH_4 to Cl_2 must be

Answer»

HIGH
low
equal
can't be PREDICTED

SOLUTION :High
Discussion
41.

CH_4 can be prepared by the reaction of H_2O with

Answer»

`Mg_2C_3`
`CaC_2`
`Be_2C`
`Al_4C_3`

SOLUTION :`Be_2C + 4H_2O to CH_4 + 2Be(OH)_2`
` Al_4C_3 + 12H_2O to 3CH_4 + 4AL(OH)_3`
Discussion
42.

CH_3underset(Br)underset(|)CH=underset(Br)underset(|)CH_2 underset( " of alc." KOH)overset("1 equivalent")to The major product is

Answer»

`CH_3CH = CHBR`
`CH_2 = CHCH_2 Br`
`CH_3underset(Br)UNDERSET(|)C=CH_2`
NONE of these

Solution :`CH_3 - underset(Br)underset(|)CH-underset(Br)underset(|)CH_2 underset (1 mol)overset(alc. KOH)to CH_3CH = CHBr`
Discussion
43.

CH_3OH_((l)) underset"673 K"overset"50 bar"to CO_((g)) + 2H_(2(g)) Which catalyst is used in the above reaction.

Answer»

COPPER OXIDE
IRON chromate
Cuprous oxide
Nickel

Answer :C
Discussion
44.

CH_3OH, methanol can be prepared from CO and H_2. CO(g)+2H_2(g)hArr CH_3OH(g) The value of K_p at 500 K is 6.23xx10^(-3) When total pressure (in atm) at equilibrium is required to convert 25% of CO to CH_3OH at 500 K if CO and H_2 comes from CH_4(g)+H_2O(g) to CO(g)+3H_2(g) Given your answer excluding decimal places.

Answer»


ANSWER :10
Discussion
45.

CH_(3)Mgloverset(C_(2)H_(5)OH)toX+C_(2)H_(5)OMgl The product X is........

Answer»

`CH_(4)`
`C_(2)H_(6)`
HCHO
`CH_(3)OH`

Answer :A
Discussion
46.

CH_(3)COOK_((aq))overset("Electrolysis")rarrAunderset(1000^(@)C)overset(Delta)rarrB Bunderset(KMnO_(4))overset("Alkaline")rarrC. Here compound 'C' is

Answer»

`UNDERSET(COOH)underset("|")(CH_(3)`
`underset(CH_(2)OH)underset("|")(CH_(2)OH)`
`underset(CHO)underset("|")(CHO)`
`underset(COOH)underset("|")(COOH)`

Answer :B
Discussion
47.

CH_(3)COOH_((l)) + C_(2)H_(5)OH_((l))hArrCH_(3)COOC_(2)H_(5(l)) + H_(2)O_((l)) In the above reaction, one mole of each of acetic acid and alcohol are heated in the presence of little cone. H_(2)SO_(4). On equilibrium being attained

Answer»

1 mole of ETHYL acetate is formed
2 mole of ethyl acetate are formed
`1//2` mole of ethyl acetate is formed
`2//3` moles of ethyl acetate is formed

Solution :In presence of little `H_(2)SO_(4)` (as catalyst) about `2//3` mole of each of `CH_(3)COOH` and `C_(2)H_(5)OH` react to from `2//3` mole of the product at equilibrium.
Discussion
48.

CH_(3)COOH(l)+CH_(2)H_(5)OH(l)hArrCH_(3)COOC_(2)O(l) In the above reaction, one mole of each of acetic acid and alcohol are heated in the presence of little conc. H_(2)SO_(4). On equilibrium being attained

Answer»

`1` mole of ETHYL acetate is FORMED
`2` mole of ethyl acetate are formed
`1//2` moles of ethyl acetate is formed
`2//3` moles of ethyl acetate is formed

SOLUTION :N//A
Discussion
49.

CH_(3)COOH_((l)) + C_(2)H_(5)OH_((l))hArrCH_(3)COOC_(2)H_(5(l)) + H_(2)O_((l)) In the above reaction, one mole of each of acetic acid and alcohol are heated in the presence of little cone. H_(2)SO_(4). On equilibriumbeing attained

Answer»

1 mole of ethyl ACETATE is formed
2 mole of ethyl acetate are formed
`1//2` moles of ethyl acetate is formed
`2//3` moles of ethyl acetate is formed

Solution :In presence of little `H_(2)SO_(4)` (as catalyst) about `2//3` mole of each of `CH_(3)COOH` and `C_(2)H_(5)OH` react to from `2//3` mole of the product at equilibrium.
Discussion
50.

CH_(3)COOH, when reacts with C_(2)H_(5)OH, gives a product. The same product is obtained with which reaction ?

Answer»

ACETIC ACID + methanol
Acetic ANHYDRIDE + water
Acetic angydride + ethanol
Acetamide + methanol

Answer :C
Discussion