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31001.

The decreasing order of bond angles from NH_(3) (106^(@)) to SbH_(3)(101^(@)) down group 15 of the periodic table is due to:

Answer»

INCREASING bp - LP repulsion.
increasingp CHARACTER in `sp^(3)`
decreasing lp - bp replusion.
decreasing electronagetivity.

Answer :C
Discussion
31002.

The decreasing order of boiling points of alkyl halides is

Answer»

`RF gt RCl gt RBr gt RI`
`RBr gt RCl gt RI gt GF`
`RI gt RBr gt RCl gt RF`
`RI gt RF gt RCl gt RBr`

SOLUTION :For the same alkyl group, the boiling points of alkyl halides decrease in the ORDER: RIgtRBrgtRClgtRF
Thisis because with the INCREASE in size and mass of halogen atom, the magnitude of VANDER WAAL's forces increase.
Discussion
31003.

The decreasing order of boiling points of the following alcohols is

Answer»

3 - methylbutan -2- OL `gt` 2 - methylbutan -2- ol `gt` PENTAN -1- ol
pentan -1- ol `gt` 3 - methylbutan -2- ol `gt` 2 - methylbutan -2- ol
2 - methylbutan -2- ol `gt` 3 - methylbutan -2- ol `gt` pentan -1- ol
2 - methylbutan -2- ol `gt` pentan -1- ol `gt` 3 - methylbutan -2- ol

Answer :B
Discussion
31004.

The decreasing order of boiling points of isomeric pentanes is -

Answer»

n-pentane `GT` ISOPENTANE `gt` NEOPENTANE
isopentane `gt` n-pentane `gt` neopentane
neopentane `gt` isopentane `gt` n-pentane
n-pentane `gt` neopentane `gt` isopentane

Answer :A
Discussion
31005.

The decreasing order of basicity of nitrogen in the following compounds is : (a) CH_(3)-CH_(2)-NH_(2),C_(6)H_(5)-NH_(2),H_(2)C=CH-NH_(2) (b) (C_(6)H_(5))_(3)N,(C_(6)H_(5))_(2)NH,C_(6)H_(5)NH_(2) (c) H_(2)C=NH,HCN,CH_(3)NH_(2) (d) C_(6)H_(5)NH_(2),C_(6)H_(11)NH_(2),C_(6)H_(5)CONH_(2) (e) C_(5)H_(5)N,C_(4)H_(4)NH,C_(6)H_(5)NH_(2),CH_(3)CONH_(2) (f) C_(6)H_(5)N(CH_(3))_(2),C_(6)H_(3)(CH_(3))_(2)N(CH_(3))_(2),C_(6)H_(5)NH_(2) (g) H_(2)N-C_(6)H_(4)-OCH_(3),C_(6)H_(5)NH_(2), H_(2)N-C_(6)H_(4)-NO_(2),H_(2)N-C_(6)H_(4)-CH_(2), H_(2)N-C_(6)H_(4)-Cl (h) {:(C_(6)H_(5)-underset("NH")underset("|| ")"C "-NH_(2)","O_(2)N-C_(6)H_(4)-underset("NH")underset("|| ")"C "-NH_(2)),(Cl-C_(6)H_(4)-underset("NH")underset("|| ")"C "-NH_(2)","H_(2)N-C_(6)H_(4)-underset("NH")underset("|| ")"C "-NH_(2)):}

Answer»

Solution :

HIGHER the PERCENTAGE of s-character, the more tightly lone pair is held, and the weaker the base.

Ganidine is strongly basic
Basicity of DIFFERENT nitrogen containing compounds is :
[Guanidine gt aliphatic amines gt `NH_(3)` gt aromatic amines gt AMIDES gt cyanide]
Discussion
31006.

The decreasing order of boiling points of 1^@,2^@,3^@ alcohol is :

Answer»

`1^@ GT 2^@ gt 3^@`
`3^@ gt 2^@ gt 1^@`
`2^@ gt 1^@ gt 3^@`
None

Answer :A
Discussion
31007.

The decreasing order of basic character of K_2O, BaO, CaO and MgO is

Answer»

`K_2O GT BaO gt CaO gt MgO`
`K_2O gt CaO gt BaO gtMgO`
`MgO gt BaO gt CaO gt K_2O`
`MgO gt CaO gt BaO gt K_2O`

Solution :ALKALI metal OXIDES are very much basic. Down the group in the alkaline earth metal series, ionisation POTENTIAL DECREASES.
Discussion
31008.

The decreasing order of basicity of alcohols are

Answer»

`3^@ GT 2^@ gt 1^@`
`3^@ gt 1^@ gt 2^@`
`2^@ gt 3^@ gt 1^@`
`1^@ gt 2^@ gt 3^@`

ANSWER :A
Discussion
31009.

The decreasing order of aromaticity fo the following is I. Benzene, II. Napthalene, III. Anthrance

Answer»

`(I) gt (II) gt (III)`
(IIII) gt (II) gt (I)`
`(II) gt (I) gt (III)`
`(II) gt (IIII) gt (I)`

Solution :`R.E`. Of benzene napathalene and anthrancene, respectively are `151,255`, and `351 KJ MOL^(-1)`
`E.E.//` ring of napthalene (two rings) `= 255//2`
`= 127.5 kJ mol^(-1)`
`R.E.//"ring"` of anthrance (THREE rings) `= 351//3`
`= 117 kJ mol^(-1)`
On the basic of `R.E.//"ring", R.E`. of `"benzene"gt"of napathalene" gt "of anthrance".
Discussion
31010.

The decreasing order of acidity among th following compounds, ethanol (I), 2,2,2-trifluoroethanol (II), trifluoroacetic acid (III) and acetic acid (IV) is

Answer»

IIIgtIIgtIVgtI
IVgtIIIgtIIgtI
IgtIIgtIIIgtIV
IIIgtIVgtIIgtI

Solution :Carboxylic acids are STRONGER acids than alcohols and fluoroacids are stronger acids than unsubstituted acids and fluoroalcohols are stronger acids than unsubstituted alcohols. THUS, acidity decreases in the order: trifluoroacetic acid (III)gt acetic acid (IV) gt TRIFLUOROETHANOL (II)gt ethanol (I) i.e., option (d) is correct.
Discussion
31011.

The decreasing order of acidity of the following acids is : (1) Ethanoic acid(2) Chloroethanoic acid(3) Trichloroethanoic acid(4) Trifluoroethanoic acid

Answer»

`4gt3gt2gt1`
`3gt4gt2gt1`
`1gt2gt3gt4`
`2gt1gt3gt4 `

ANSWER :A
Discussion
31012.

The decreasing order of acidic character among ethane (I), ethene (II),ethyne (III) and propyne (IV) is

Answer»

(I) gt (II) gt (III) gt (IV)
(II) gt (III) gt (I) gt (IV)
(III) gt (IV) gt (II) gt (I)
(IV) gt (III) gt (II) gt (I)

Solution :The CORRECT order of decreasing acidity is `underset"(III)"(CH-=CH)gt underset"(IV)"(CH-=C-CH_3)gt underset"(II)"(CH_3=CH_2)gt underset"(I)"(CH_3-CH_3)`
Hydrocarbon ATOMS attached to sp-hybridised carbon atom are most ACIDIC , FOLLOWED by those attached to `sp^2`-hybridised carbon -atom, and those attached to `sp^3`-hybridised carbon are least acidic.
Discussion
31013.

The decreasing nucleophilic order of the following compounds is: i. PhSO_(3)^(o-), ii. C_(2)H_(5)SO_(3)^(o-), iii. C_(2)H_(5)COO^(o-), iv. overset(o-)(C)N, v. overset(o-)(O)H

Answer»

`(v) gt (iv) gt (III) gt (ii) gt (i)`
`(i) gt (ii) gt (iii) gt (iv) gt (v)`
`(iv) gt (v) gt (iii) gt (ii) gt (i)`
`(i) gt (ii) gt (iii) gt (v) gt (iv)`

SOLUTION :Nucelphilic centre on `overset(o-)(C)N` is different from others, but belongs to the same period. Basic and nucelophilic ORDERS are same.
Discussion
31014.

The decreasing nucleophillic order fo the following compounds is: i. F^(o-), ii. Cl^(o-), iii. Br^(o-), Iv. I^(o-)

Answer»

`(i) gt (II) gt (iii) gt (IV)`<BR>`(iv) gt (iii) gt (ii) gt (i)`
`(ii) gt (i) gt (iii) gt (iv)`
`(ii) gt (i) gt (iv) gt (iii)`

Solution :SINCE nucleopphilic centre is different and they belong to the same group, so BASIC character and nuclophilicy are reversed.
`I^(o-) gt Br^(o-) gt Cl^(o-) gt F^(o-)`
Discussion
31015.

The decreasing nucleophilic order of the followingcompounds is: i. NH_(3), ii. PH_(3), iii. AsH_(3), iv. SbH_(3)

Answer»

`(i) gt (ii) gt (iii) gt (iv)`
`(iv) gt (iii) gt (ii) gt (i)`
`(ii) gt (i) gt (iii) gt (iv)`
`(ii) gt (i) gt (iv) gt (iii)`

Solution :SINCE nucleophilic centre is DIFFERENT ad belongs to the same groupso basic character and nuclophilicity are reversed. `SbH_(3) gt AsH_(3) gt Ph_(3) gt NH_(3)`
Discussion
31016.

The decreasing nucelophilic order of the following compoundsis: i. overset(o-)(C)H_(3), ii. Overset(o-)(O)H, iii.CH_(3)COO^(o-), iv. H_(2)O

Answer»

`(i) GT (ii) gt (iii) gt (iv)`
`(iv) gt (iii) gt (ii) gt (i)`
`(iiii) gt (i) gt (ii) gt (iv)`
`(iii) gt (ii) gt (iv) gt (i)`

SOLUTION :Compared to the others, `overset(io-)(C)H_(3)` has different nuclophillic centre, however it belongs to the same period. Basically and nucelophilicity order the same.
`overset(o-)(C)H_(3) gt overset(o-)(O)H gt CH_(3)COO^(o-) gt H_(2)O`
Discussion
31017.

The decreasing nucleophilic oder of the following compounds is: i. overset(o-)(C)H_(3), ii. overset(o-)(N)H_(2), iii. overset(o-)(O)H, iv. F^(o-)

Answer»

`(i) gt (ii) gt (iii) gt (iv)`
`(iv) gt (iii) gt (ii) gt (i)`
`(ii) gt (i) gt (iii) gt (iv)`
`(ii) gt (i) gt (iv) gt (iii)`

Solution :Since the NUCELPHILIC centre is different but they belong to the same period. So the basic and nuclophilic characters are same. Basically and nuclophilicity
`C overset(o-)(H_(3) gt overset(o-)(N) H_(2) gt overset(o-)(O) H lt F^(o-)`
Discussion
31018.

The decreasingnucelophilic order of the following compounds is: i. NH_(3), ii. PH_(3), iii. AsH_(3), iv. SbH_(3)

Answer»

`(i) gt (ii) gt (III) gt (iv)`
`(iv) gt (iii) gt (ii) gt (i)`
`(ii) gt (i) gt (iii) gt (iv)`
`(ii) gt (i) gt (iv) gt (iii)`

SOLUTION :Weaker the base or stornger the ACID, stonger is the leaving group.
`SbH_(3) gt AsH_(3) gt PH_(3) gt NH_(3)`
Discussion
31019.

The decreasing nucelophilc order of the following compounds is: i. overset(o-)(C)N, ii. overset(o-)(O)H, iii. overset(o-)(O) Me, iv. overset(o-)(C)H_(3), v. H^(o-)

Answer»

`(v) gt (iv) gt (III) gt (ii) gt (i)`
`(i) gt (ii) gt (iii) gt (iv) gt (v)`
`(iv) gt (v) gt (iii) gt (ii) gt (i)`
`(i) gt (ii) gt (iii) gt (v) gt (iv)`

Solution :DIFFERENT NUCLEOPHILIC centres in `C^(o-)N. H^(o-), C^(o-)H_(3)`, but all belong to the same PERIOD.
Basic and nucleophicl orders are same.
Discussion
31020.

The decreasing leaving group order of the following is: i. F^(o-), ii. Cl^(o-), iii. Br^(o-), Iv. I^(o-)

Answer»

`(i) GT (II) gt (iii) gt (IV)`
`(iv) gt (iii) gt (ii) gt (i)`
`(ii) gt (i) gt (iii) gt (iv)`
`(ii) gt (i) gt (iv) gt (iii)`

Solution :Weaker the base or stronger the ACID, stronger is the leaving GROUP.
`I^(o-) gt Br^(o-) gt Cl^(o-) gt F^(o-)`
Discussion
31021.

The decreasing leaving group order of the following is: i. F_(3)CSO_(3)^(o-), ii. Cl_(3)C-COO^(o-) iii. PhSO_(3)^(o-), iv. MeSO_(3)^(o-)

Answer»

`(i) GT (ii) gt (III) gt (IV)`
`(iv) gt (iii) gt (ii) gt (i)`
`(IIII) gt (i) gt (ii) gt (iv)`
`(i) gt (iii) gt (ii) gt (i)`

Solution :Nucelphilicity and LEAVING group are reversed.
Fugavity: `(i) gt (iii) gt (Iv) gt (ii)`
Discussion
31022.

The decreasing leaving group order (fugacity order) of the following compounds is: i. H_(2)O, ii. H_(2)S, iii. H_(2)Se, iv. H_(2)Te

Answer»

`(i) GT (ii) gt (III) gt (IV)`
`(iv) gt (iii) gt (ii) gt (i)`
`(iiii) gt (i) gt (ii) gt (iv)`
`(iv) gt (ii) gt (i) gt (iii)`

Solution :Weaker the base, stronger is the leaving GROUP.
Fugacity: `H_(2) TE gt H_(2) Se gt H_(2) S gt H_(2)O`
Discussion
31023.

The decreasing basic order of the following is: i. PhSO_(3)^(o-), ii. C_(2)H_(5)SO_(3)^(o-), iii. C_(2)H_(5)COO^(o-), iv. overset(o-)(C)N, v. overset(o-)(O)H

Answer»

`(v) gt (iv) gt (iii) gt (ii) gt (i)`
`(i) gt (ii) gt (iii) gt (iv) gt (v)`
`(iv) gt (v) gt (iii) gt (ii) gt (i)`
`(i) gt (ii) gt (iii) gt (v) gt (iv)`

Solution :ACIDIC: `PhSO_(3)H gt C_(2)H_(5)SO_(3)H gt C_(2)H_(5)COOH gt HCN gt H_(2)O`
BASIC:
`PhSO_(3)^(o-) lt C_(2)H_(5)SO_(3)^(o-) lt C_(2)H_(5)COO^(o-) lt overset(o-)(C)N lt overset(o-(O)H`
Discussion
31024.

The decreasing fugacity order of the following compounds is: i. PhSO_(3)^(o-), ii. C_(2)H_(5)SO_(3)^(o-), iii. C_(2)H_(5)COO^(o-), iv. overset(o-)(C)N, v. overset(o-)(O)H

Answer»

`(V) GT (iv) gt (iii) gt (II) gt (i)`
`(i) gt (ii) gt (iii) gt (iv) gt (v)`
`(iv) gt (v) gt (iii) gt (ii) gt (i)`
`(i) gt (ii) gt (iii) gt (v) gt (iv)`

Solution :Fugacity and BASIC orders are reversed.
`(i) gt (ii) gt (iii) gt (iv) gt (v)`
Discussion
31025.

The decreasing fugacity order of the following is: i. overset(o-)(C)N, ii. overset(o-)(O)H, iii. overset(o-)(O) Me, iv. overset(o-)(C)H_(3), v. H^(o-)

Answer»

`(v) gt (IV) gt (iii) gt (ii) gt (i)`
`(i) gt (ii) gt (iii) gt (iv) gt (v)`
`(iv) gt (v) gt (iii) gt (ii) gt (i)`
`(i) gt (ii) gt (iii) gt (v) gt (iv)`

SOLUTION :BASICALLY and fugacity REVERSED.
Discussion
31026.

The decreasing basic order of the following is: i. overset(o-)(C)H_(3), ii. Overset(o-)(O)H, iii.CH_(3)COO^(o-), iv. H_(2)O

Answer»

`(i) gt (ii) gt (iii) gt (iv)`
`(iv) gt (iii) gt (ii) gt (i)`
`(iiii) gt (i) gt (ii) gt (iv)`
`(iii) gt (ii) gt (iv) gt (i)`

Solution :Acidic: `H_(3) O^(o+) gt CH_(3) COOH gt H_(2)O gt CH_(4)`
BASIC: `H_(2)O LT CH_(3)COO^(o-) lt overset(o-)(O)H lt overset(o-)(C) H_(3)`
Discussion
31027.

The decreasingbasic order of the following is: i. overset(o-)(C)H_(3), ii. overset(o-)(N)H_(2), iii. overset(o-)(O)H, iv. F^(o-)

Answer»

`(i) gt (ii) gt (III) gt (iv)`
`(iv) gt (iii) gt (ii) gt (i)`
`(ii) gt (i) gt (iii) gt (iv)`
`(ii) gt (i) gt (iv) gt (iii)`

Solution :Stronger the acid, weaker is its `C_(B)`
Acidic: `HF gt dot(H)_(2) O gt NH_(3) gt CH_(4)`
Basic: `F^(o-) lt overset(o-)(O)H lt overset(o-)(N)H_(2) MLT C overset(o-)(H_(3)`
Discussion
31028.

The decreasing basic order of the following is: i. F^(o-), ii. Cl^(o-), iii. Br^(o-), Iv. I^(o-)

Answer»

`(i) gt (II) gt (iii) gt (iv)`
`(iv) gt (iii) gt (ii) gt (i)`
`(ii) gt (i) gt (iii) gt (iv)`
`(ii) gt (i) gt (iv) gt (iii)`

Solution :Stronger the acid, weaker is its `C_(B)`.
Acidic: `Hl gt HBr gt HCl gt HF`
Basic: `I^(o-) LT Br lt Cl^(o-() lt F^(o_)`
Discussion
31029.

The decreasing basic order of the followingcompounds is: i. NH_(3), ii. PH_(3), iii. AsH_(3), iv. SbH_(3)

Answer»

`(i) gt (ii) gt (iii) gt (iv)`
`(iv) gt (iii) gt (ii) gt (i)`
`(ii) gt (i) gt (iii) gt (iv)`
`(ii) gt (i) gt (iv) gt (iii)`

SOLUTION :The basic character of hydrides of 15 groups DECREASES dwon the perodic table becausesize increases down the GROUP and `LP overline(e)'s` density decreases.
NH_(3) gt PH_(3) gt AsN_(3) gt Sbh_(3)`.
Discussion
31030.

The decreasing basic order of the following compounds is: i. H_(2)O, ii. H_(2)S, iii. H_(2)Se, iv. H_(2)Te

Answer»

`(i) GT (ii) gt (iii) gt (iv)`
`(iv) gt (iii) gt (ii) gt (i)`
`(iiii) gt (i) gt (ii) gt (iv)`
`(iv) gt (ii) gt (i) gt (iii)`

Solution :The basic character FO hydrides of 16 GROUP decreases down the group. Size increases down the group and `LP overline(E)` density decreases.
Basic: `H_(2)O gt H_(2)S gt H_(2)Se gt H_(2)TE`
Discussion
31031.

The decrease in the ionisation of H_2S in the presence of HCl is due to :

Answer»

SOLUBILITY product
Dilation
Common ION effect
saturation

Answer :C
Discussion
31032.

The decrease in the size of innce transition element is q

Answer»

more
less
not regular
none of these

Solution :We know that from CE to lu atomic number increaes by 14, the decrease in atomic and ionic SIZE is very small only 10 pm and 18 pm respectively. This is very small in comparison to elements of the other PERIODS. This is due to poor shielding of 4f electrons.
Discussion
31033.

The decrease in electrical conductivity of metals with increase in temperature is due to increase in

Answer»

the velocity of ELECTRONS
the RESISTANCE of the metal
the NUMBER of electrons
the number of metal atoms
Discussion
31034.

The decrasing basic order of the following is: i. Me_(2)N - Nme_(2), ii. MeNH-NHMe iii. H_(2)N - NH_(2), iv. NH_(3)

Answer»

`(i) gt (ii) gt (III) gt (IV)`
`(iv) gt (iii) gt (ii) gt (i)`
`(iv) gt (iii) gt (i) gt (ii)`
`(iii) gt (iv) gt (ii) gt (i)`

Solution :More `N` atom and more alkylgrou(`+I` EFFECT) more BASIC: `(i0 gt (ii) gt (iii) gt (iv)`.
Discussion
31035.

The decreaing basic order of the following is: i. overset(o-)(C)N, ii. overset(o-)(O)H, iii. overset(o-)(O) Me, iv. overset(o-)(C)H_(3), v. H^(o-)

Answer»

`(v) gt (iv) gt (iii) gt (ii) gt (i)`
`(i) gt (ii) gt (iii) gt (iv) gt (v)`
`(iv) gt (v) gt (iii) gt (ii) gt (i)`
`(i) gt (ii) gt (iii) gt (v) gt (iv)`

Solution :Acidic: `HCN gt MeOH gt H_(2)O gt H_(2) gt CH_(4)`
Basic: `C overset(o-)(N) lt MEO^(o-) lt OH^(o-) lt H^(o-) lt C^(o-)H_(3)`
Discussion
31036.

The decrasing fugacity order of the following compoundsis: i. overset(o-)(C)H_(3), ii. Overset(o-)(O)H, iii.CH_(3)COO^(o-), iv. H_(2)O

Answer»

`(i) gt (II) gt (iii) gt (iv)`
`(iv) gt (iii) gt (ii) gt (i)`
`(iiii) gt (i) gt (ii) gt (iv)`
`(iii) gt (ii) gt (iv) gt (i)`

SOLUTION :Fugacity and basically orders are reversed.
`H_(2)O gt CH_(3)COO^(o-) gt OVERSET(o-)(C) H_(3)`
Discussion
31037.

The decompostion of N_(2)O_(5 (g)) to NO_(3(g)) Proceeds as a first order reaction with a half-life period of 30 seconds at a certain temperature . If the initial concentration [N_(2)O_(5)]= 0.4 M , what is the rate constant of the reaction

Answer»

`0.00924 sec^(-1)`
`0.0231 sec^(-1)`
`75 sec^(-1)`
`12 sec^(-1)`

Solution :For a FIRST ORDER REACTION , k `= (0.693)/(t_(1//2)) = (0.693)/(30) = 0.0231 sec^(-1)`
Discussion
31038.

The decompostion of potassium chlorate speed up in the presence of …………… .

Answer»

`MnO_(2)`
`Mn_(3)O_(4)`
`MnSO_(4)`
`KMnO_(4)`

SOLUTION :`MnO_(2)`
Discussion
31039.

The decompostion of N_(2)O into N_(2) and O_(2) in presence of Argon follows first order kinetics k=5.0xx10^(11)e^(-2000//T(K)). The activation energy is

Answer»

`16.628kJ"mol"^(-1)`
`166.28kJ"mol"^(-1)`
`166.28J"mol"^(-1)`
`16.628J"mol"^(-1)`

Solution :`K=(5xx10^(11)).E^((-200)/T),K=A.e^((-EA)/(RT)),(-2000)/T=(-Ea)/(RT)`
`epsilon_(a)=2000xxR=20000xx8.3.4=16.628,epsilon_(a)=16.628`KJ/mole
Discussion
31040.

The decomposittion reaction of ammonia gas on platinum surface has a rate constant =2.5xx10^(-4)" mol L"^(-1)s^(-1). What is the order of the reaction ?

Answer»

SOLUTION :ZERO ORDER (on the BASIS of units of K)
Discussion
31041.

The decomposition reaction of ammonia gas on platinum surface has a rate constant R = 2.5xx10^(-4)"mol L"^(-1). What is the order of the reaction.

Answer»

SOLUTION :The ORDER of the REACTION is ZERO.
Discussion
31042.

The decomposition ofdimethyl ether leads to the formation of CH_4, H_2 and CO and the reaction rate isgiven by Rate = k[CH_2OCH_2]^(3//2). The rate of reaction is followed by increase in pressure in a closed vessel and the rate can also be expressed in term s of the partial pressure of dimethyl ether i.e., Rate = k[P_(CH_3OCH_3)]^(3//2). If the pressure is measured in bar and time in minutes, then what are the units of rate and rate constants?

Answer»

SOLUTION :BAR^(-1//2) "MIN"^(-1)`
Discussion
31043.

The decomposition reactiom of SO_(2)Cl_(2) is the first order reaction.It.s concentration gets halved in 60 minutes what is its rate constant value?

Answer»

0.01155 `MIN^(-1)`
0.07676 `min^(-1)`
0.7676 `min^(-1)`
0.1155 `"MINUTE"^(-1)`

ANSWER :A
Discussion
31044.

The decomposition of phosphine, PH_(3), proceeds according to the following equation: 4PH_(3)(g) to P_(4)(g) +6H_(2)(g) It is found that the reaction follows the following rate equation: Rate =k[PH_(3)]. The half-life of PH_(3) is 37.9s at 120^(@)C. (i) How much time is required for 3//4th of PH_(3) to decompose? (ii) What fraction of the original sample of PH_(3) remains behind after 1 minute?

Answer»

Solution :`4PH_(3)(g) to P_(4)(g) +6H_(2)(g)`
Half-life of `PH_(3)=37.9s`
Rate `=k[PH_(3)]`
This MEANS that the reaction is of first order. For a first order reaction
`k=(0.693)/(t_(1//2)) or k=(0.693)/(37.9)=0.01828496`
(i) Apply the relation
`k=(2.303)/(t) "log"([R]_(0))/(R )`
Here `R=R_(0)-(3)/(4)R_(0)=(R_(0))/(4)`
Substituting the values in the equation above, we have
`0.01828496=(2.303)/(t)"log"([R]_(0))/([R_(0)]//4)`
or `t=(2.303)/(0.01828496)log 4 or t=(2.303)/(0.01828496)xx 0.60206=75.83s`
(ii) After 1 minute or 60 seconds
`k=(2.303)/(t)"log"([R]_(0))/(R ) or " log"([R]_(0))/(R )=(kt)/(2.303)`
Substituting the values, we have
`"log"([R]_(0))/(R )=(0.0183xx60)/(2.303)=0.4768`
Taking antilogarithm, we have
`([R]_(0))/(R )=2.992 or (R )/([R]_(0))=(1)/(2.992)=0.3342`
Discussion
31045.

The decomposition of phosphine (pH_(3))on tungsten at low pressure is a first-order reaction .It is because the ……..

Answer»

rate is independent of the surface COVERAGE.
rate of DECOMPOSITION is very slow.
rate is PROPORTIONAL to the surface coverage
rate is inversely proportional to the surface coverage

Solution :The decompositional to the surface coverage pressure is a first order REACTION because rate is proportional to the surface coverage
Discussion
31046.

The decomposition of phosphine (PH_(3)) on tungsten at low pressure is a first-orfer reaction . It is because the

Answer»

RATE of decomposition is very slow
Rate is proportional to the surface coverage
Rate is inversely proportional to the surface coverage
Rate is INDEPENDENT of the surface coverage

Solution :`PH_(3) overset(W) (to) P + (3)/(2) H_(2) ""` Rate = `k[PH_(3)]`
It is independent of the the surface coverage because ZERO ORDER REACTION depend on surface area covered by reactant .
Discussion
31047.

The decomposition of phosphine (PH_(3)) on tungsten at low pressure is a first - order reaction. It is because the

Answer»

Rate is PROPORTIONAL to the SURFACE coverage
Rate is inversely proportional to the surface coverage
Rate is independent of the surface coverage
Rate of DECOMPOSITION is very slow

Answer :A
Discussion
31048.

The decomposition of phosphine (PH_3) on tungsten at low pressure is a first order reaction . It is because the ..................[NEET]

Answer»

rate is proportional to the surface converge
rate is inversely proportional to the surface converge
rate of decomposition is slow
rate is independent of the surface

Solution :At low pressure the reaction follows first order , THEREFORE Rate `prop ["reactant"]^(-1)`
Rate `prop` (surface AREA)
At HIGH pressure due to the complete coverage of surface area. The reaction follows ZERO order.
Rate `prop ["reaction"]^0`
Therefore the rate is independent of surface area. .
Discussion
31049.

The decomposition of phosphine (PH_(3)) on tungsten at low pressure is a first-order reaction. It is because the-

Answer»

rate of DECOMPOSITION is very low
rate is PROPORTIONAL to the surface coverage
rate is INVERSELY proportional to the surface coverage
rate the independent of the surface coverage

Answer :B
Discussion
31050.

The decomposition of ozone proceeds as : O_(3) rarr O_(2) + O (fast) O+ O_(3) rarr 2O_(2) (slow ) The rate expression should be :

Answer»

Rate = `k[O_(3)]^(2) `
Rate = `k[O_(3)]^(2) [O_(2) ]^(-1)`
Rate `=k[O_(3)][O_(2)]`
Rate `= k [O_(3)] [O_(2)]^(-1)`

Solution :(B) k =`([O][O_(2)])/([O_(3)])`
or `[O] = k ([O_(3)])/([O_(2)])`
`:. "Rate" = (k[O_(3)][O_(3)])/([O_(2)])=[O_(3)]^(2)[O_(2)]^(-1)`
Discussion