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25551.

The pressure of the water vapour of a solution containing a nonvolatile solute is 2% below that of the vapour of pure water. Calculate the molality of the solution.

Answer»


ANSWER :1.134
Discussion
25552.

The pressure of the water vapour of a solution containing a nonvolatile solute is 2% below that of the vapour of pure water. Determine the molality of the solution.

Answer»


ANSWER :`1.134m`
Discussion
25553.

The pressure of the gas was found to decrease from 720 to 480 m. When 5g of sample of activated charcoal was kept in a flask of one litre capacity maintained at 27^(@)C . If the density of charcoal at 1.25 gm//mL. The volume of gas adsorbed per gm of charcoal at 480 mm of Hg is

Answer»

`80.03 mL`
`32.20 mL`
`100.08mL`
None of these

Solution :`V_(2)=(P_(1)V_(1))/(P_(2))=(720xx1000)/(480)=1500ml`
Volume of gas in the FLASK `=1000-` volume of charcoal `1000-(5)/(1.25)=996ml`
TOTAL volume of gas adsorbe by charcoal `=1500-996=504ml`
Volume of gas adsorbe by per GRAM of charcoal `=(504)/(5)=100.08ml`
`V_(2)=(P_(1)V_(1))/(P_(2))=(720xx1000)/(480)=1500ml`
Discussion
25554.

The pressure of H_(2) required to make the potential of H_(2)-electrode zero in pure water at 298K is

Answer»

<P>`10^(-14)atm`
`10^(-12)atm`
`10^(-10)atm`
`10^(-4)atm`

Solution :`2H^(+)(aq)=2e^(-)toH_(2)(g)`
`thereforeE=E^(0)-(0.0591)/(2)"log"(P_(H_(2)))/([H^(+)]^(2))`
`0=0-0.295"log"(P_(H_(2)))/((10^(-7))^(2))`
`(P_(H_(2)))/((10^(-7))^(2))=1`
`P_(H_(2))=10^(-14)atm`
Discussion
25555.

The pressure of real gases is less than that of ideal gas because of

Answer»

increase in the kinetic ENERGY of the molecules
intermolecular attraction
finite size of particles
increase in the number of collisions.

Solution :The GAS molecules have ATTRACTIVE forces between them due to which the observed PRESSURE is less than the ideal pressure
Discussion
25556.

The pressure of real gas is less than the pressure of an ideal gas because of :-

Answer»

INCREASE in NUMBER of collisions
Finite SIZE of molecule
Increase in KE of molecules
Intermolecular FORCES of attraction

Answer :D
Discussion
25557.

The pressure of H_(2) required to make the potential of H_(2)- electrode zero in pure water at 298 K is

Answer»

`10^(-10)m`
`10^(-4)atm`
`10^(-14)atm`
`10^(-12)atm`

SOLUTION :The reduction REACTION for `H_(2)`-electrode is
`2H^(+)(AQ)+2^(-)toH_(2)(g)`
`H_(H^(+)//H_(2))^(@)=E_(H^(+)//H_(2))^(@)-(0.0591)/(2)"log"(p_(H_(2)))/([H^(+)]^(2))`
In pure WATER at 298K, `[H^(+)]=10^(-7)M`
`therefore0=0-(0.0591)/(2)"log"(p_(H_(2)))/((10^(-7))^(2))`
or `"log"(p_(H_(2)))/(10^(-14))=0` or `(p_(H_(2)))/(10^(-14))=1""(becauselog1=0)`
or `p_(H_(2))=10^(-14)atm`
Discussion
25558.

The pressure of an ideal gas undergoin isothermal change is increased by 10%. The volume of the gas must decrease by about

Answer»

<P>`0.1%`
`9%`
`10%`
`0.9%`

Solution :Giventhat `DELTAP =(10)/(100)xx p= 0.1p`
Now `(p+Deltap) =11p`
From `Delta v = ((v-v)/(v)) xx 100`
`=(1-(10)/(11))xx 100 =9%`
Discussion
25559.

The pressure of a real gas is less than the pressure of an ideal gas because of :

Answer»

INCREASE in the NUMBER of collisions
Finite SIZE of the molecules
Increase in the KINETIC energy
Intermolecular forces

Answer :D
Discussion
25560.

The pressure of a gas decomposing at the surface of a solid catalyst has been measured different times and the results are given below t (sec)0100200300 Pr. (Pascal) 4xx10^(3) 3.5xx10^(3) 3xx10^(3) 2.5xx10^(3) Determine the order of reaction, its rate constant.

Answer»

Solution :(i) ZERO order, (II) `K=(5Pa)/(a)`
Discussion
25561.

The pressure of a gas is due to :

Answer»

The COLLISION of GAS MOLECULES against each other
The random movement of gas molecules
The INTERMOLECULAR forces of attraction between the gas molecules
The collision of gas molecules against the walls of the container

Answer :D
Discussion
25562.

The pressure of a fixed amount of an ideal gas is proportional to its temperature . Frequency of collision and their impact both increase in proportion to the square root of temperature . True// false.

Answer»


ANSWER :Both STATEMENTS are CORRECT
Discussion
25563.

The pressure of a 1:4 mixture of dihydrogen and dioxygen enclosed in a vessel is one atmosphere. What would be the partial pressure of dioxygen ?

Answer»

`0.8 xx 10^(5) `atm
`0.008 Nm^(-2)`
`8 xx 10^(4) Nm^(-2)`
0.25 atm

Solution :Partial PRESSURE of `O_(2) = ` Mole fraction of `O_(2) xx` Total pressure of mixture
`= ( 4)/( 5) xx1 = 0.8 xx 10^(5) Nm^(-2)`
or `= 8 xx 10^(4) Nm^(-2)`
Discussion
25564.

The pressure of 2 moles of an ideal gas at 273^(@)C occupying a volume of 44.8L is :

Answer»

<P>2 ATM
1 atm
3 atm
4 atm

Solution :`p = ( NRT)/( V ) = ( 2 xx 0.082xx54.6)/( 44.8)= 2 atm`
Discussion
25565.

The pressure in a vessel that contained pure oxygen dropped from 2000 mm to 1500 mm in 46 minutes as the oxygen leaked through a small hole into vacuum. When the same vessel was filled with another gas, the pressre dropped from 2000 mm to 1500 mm is 74 minutes. What is the molecular weight of the gas ?

Answer»


ANSWER :79
Discussion
25566.

The pressure of 2 moles of a gas which is confined in a2 L vessel at 20 K, if the standard conditions were P = 1 atm, T = 40 K and volume of one mole of a gas under these conditions were 10 litres.

Answer»

5 ATM
`1.642` atm
3 atm
6 atm

SOLUTION :N/A
Discussion
25567.

The pressure in a bulb dropped from 2000 mm to 1500 mm Hg in 47 minites when the contained oxygen leaked through a small hole. The bulb was the completely evacuated. A mixture of oxygen and another gas of molecular weight 79 in the molar ratio 1:1 at a total pressure of 4000 mm Hg was introduced. Find the molar ratio of the two gases remaining in the bulb after a period of 74 minutes.

Answer»

Solution :Suppose `p_(O_(2))` and p be the pressure-drops per minute for `O_(2)` and an unknown gas X (SAY) RESPECTIVELY.
`THEREFORE p_(O_(2)) = (2000 - 1500)/(47) = 10.64` mm/min.
`therefore (r_(O_(2)))/(r_(x)) = (p_(O_(2)))/(p_(x)) = sqrt((M_(x))/(M_(O_(2))))`
`(10.64)/(P_(x)) = sqrt((79)/(32)), p_(x) = 6.77` mm/min.
Sicne the bulb is now refilled with equal number of moles of `O_(2)` and x, the partial pressures of each gas will be 2000 mm as the TOTAL pressure is 4000 mm.
`therefore` pressure of `O_(2)` after 75 min
= partial press. of `O_(2)` - press. drop in 74 min
`= 2000 - (10.64 xx 74)`
= 1212.64 mm
and pressure of x after 74 min
= partial press. of x - press. drop after 74 min.
`("moles of " O_(2) " left after 74 min")/("moles of x left after 74 min") = ("pressure of " O_(2) " after 74 min")/("pressure of x after 74 min")`
`(1212.64)/(1499.02) = 0.8089`.
Hence, molar ratio of `O_(2)` and x after 74 minutes is 0.8089 : 1.
Discussion
25568.

The pressure exerted by of an ideal gas at t^(@)C in a vessel of volume V litre is one atm. When the temperature is increased by 10 degree at the same volume, the pressure increases by 10%. Calculate temp t and volume V (molecular weight of gas =120)

Answer»

Solution :Case (I) : GIVEN P= 1 atm, w=12 g, T=(t+273) K, V=V litre.
Case (II) : `T=t+283, P=1+(10)/(100)=1.1` atm
`W=12 g, V=V` litre.
Using equation, PV =nRT
Case (I) : `1xxV=(12)/(m) XX R (t+273)"….(1)"`
Case (II) `1.1 V =(12)/(m) xx R (t+283)"....(2)"`
By eq (1) and (2),
`(1.1)/(1)=(t+283)/(t+273)`
`therefore 1.1 t=-17.3, t=-173^(@)C=100 K`
Also from case (I), `1xx v=(12)/(120) xx0.082 xx100`
V=0.82 litre.
Discussion
25569.

The pressure exerted by 12 g of an ideal gas at temperature t^@Cin a vessel ofvolume V litre is one atm. When the temperature is increased by 10 degrees at the same volume, the pressure increases by 10%, Calculate the temperature f and volume V. (Mol wt. of the gas = 120)

Answer»

SOLUTION :APPLY pV = nRT twice
100 K, 0.821 L
Discussion
25570.

The pressure at equilibrium over solid A is 50 atm and over solid D is 68 atm if both solid A and D are heated simultaneously then find mole fraction of C

Answer»

<P>

Solution :MOLE fraction of C
`C=x/(2(x+y))`
As we KNOW `(K_(p_(1))/(K_(p_(2)))=x/yrArry/xrArry/x=(K_(p_(2)))/(K_(p_(1)))`
`rArr(x+y)/x=(K_(p_(2))+K_(p_(1)))/(K_(p_(1))),(2(x+y))/x=(2(k_(p_(2))+k_(p_(1))))/(K_(p_(1)))`
`x/(2(x+y))=(K_(p_(2)))/(2(K_(p_(2))+K_(p_(1))))`
`rArr` mole fraction of C `=(K_(p_(1)))/(2(K_(p_(2))+K_(p_(1))))`
Discussion
25571.

The pressure and temperature of 4 dm^(3) of carbon dioxide gas are doubled. Then the volume of carbon dioxide gas would be

Answer»

`2 dm^(3)`
`3 dm^(3)`
`4 dm^(3)`
`8 dm^(3)`

Solution :`(p_(1)V_(1))/( T_(1)) = ( p_(2) V_(2))/( T_(2))`
`( p XX 4)/( T ) = ( 2P xx V_(2))/( 2T)`
`:. V_(2) = 4 dm^(3)`
Discussion
25572.

The preservative which is ultimately excreted in urine as hippuric acid is

Answer»

Sodium acetate
Sodium BENZOATE
Sodium sorbate
Sodium propionate

Solution :sodium benzoate converts to HIPPURIC ACID and excretes through urine .
Discussion
25573.

The preservative which is used to preserve bread and cakes is

Answer»

SODIUM PROPIONATE
Sodium sorbate
Sodium benzoate
Sodium acetate

Solution :sodium propionate is perservative for BREADS
Discussion
25574.

The present in vitamin B_(12) is

Answer»

iron
manganese
COBALT
magnesium

Solution :Cobalt
Discussion
25575.

The present form of commercial iron is

Answer»

PIG iron
cast iron
steel
wrought iron

Answer :D
Discussion
25576.

The present of halogens in an organic compound is detected by

Answer»

IODOFORM TEST
Silver NITRATE Test
Beilstein test
MILLON's test

Answer :B
Discussion
25577.

The presence or absence of hydroxyl group on which carbon atom of sugar differentiates RNA and DNA ?

Answer»

2ND
3RD
4th
1st

Solution :Ribose contains `-OH` at `C_2` but DEOXYRIBOSE does not.
Discussion
25578.

The presence or absence of hydroxyl group on which carbon atom of sugar differentiates RNA and DNA.

Answer»

`1^(st)`
`2^(nd)`
`3^(RD)`
`4^(TH)`

Answer :B
Discussion
25579.

The presence or absence of hydroxy group on which carbon atom of sugar differentiates RNA and DNA

Answer»

1ST
2ND
3RD
4TH

SOLUTION :
Discussion
25580.

The presence or absence of hydroxyl group on which carbon atom of sugar differentiates RNA and DNA?

Answer»

`1^(st)`
`2^(ND)`
`3^(rd)`
`4^(th)`

Solution :RNA has D (-)-Ribose and the DNA has 2-Deoxy D (-)-ribose as the carbohydrate unit.

From the STRUCTURES it is clear that 2nd CARBON in DNA do not have OH GROUP.
Discussion
25581.

The presence or absence of hydroxy group on which carbon atom of sugar differentiates RNA and DNA.

Answer»

`1^(st)`
`2^(ND)`
`3^(rd)`
`4^(TH)`

ANSWER :B
Discussion
25582.

The presence or absence of hydroxy group on which carbon atom of sugar differentiates RNA and DNA ?

Answer»

`3^(rd)`
`4^(TH)`
`1^(st)`
`2^(ND)`

Answer :D
Discussion
25583.

The presence of unsaturation(olefinic or acetylinic bond ) in an organic compound can be tested with:

Answer»

SCHIFF's reagent
Tollen's reagent
Fehling solution
Baeyer's reagent

Answer :B
Discussion
25584.

The presence of Si in steel gives it

Answer»

FIBROUS structure
Silicate TYPE structure
Sheet type structure
None of these

Answer :A
Discussion
25585.

The presence of ozone (O_3) in the upper atmosphere is important, because

Answer»

`O_(3)` absorbs OUTGOING RADIATION from the earth's surface, thus helping to keep the earth warm
`O_2` absorbs harmful solar radiation
`O_3` dissolves in water droplets and is very REACTIVE
`O_3` is a MAJOR reactant in photosynthesis

Answer :B
Discussion
25586.

The presence of peroxides in old samples of ethers is detected by shaking them with a freshly prepared solution of Fe^(+)(FeSO_(4)) followed by the addition of KCNS. The appearance of ……. colour indicates the presence of peroxides.

Answer»

BLUE
Green
Red
Brown

Solution :NA
Discussion
25587.

The presence of ozone (O_3) in the atmosphere of earth

Answer»

Hinders higher RATE of photosynthesis
Helps in checking the PENETRATION of ultraviolet rays toearth
Has been responsible for increasing the average global temperature in recent years
Is ADVANTAGEOUS SINCE it supplies `O_2` for people travelling in jets

Answer :B
Discussion
25588.

The presence of -OH on adjacent carbon atoms can be detected by the reaction of the compound with-

Answer»

Conc. `H_(2)SO_(4)`
Conc. `HNO_(3)`
`HIO_(4)`
Acidic `KMnO_(4)`

Solution :
NUMBER of `KIO_(4)` required are EQUAL to total number of viccinal diol group
Discussion
25589.

The presence of nitro group (-NO_(2)) at o/p-positions increases the reactivity of haloarenes towards nucleophile substitution reactions. Give reasons.

Answer»

Solution :The presence of `-NO_(2)` groups at o/p-position withdraws electrons from the benzene RING and thus FACILITATES the ATTACK off the nucleophile on the haloarenes. Further, the carbanion thus formed is stabilized by resonance.
Discussion
25590.

The presence of NH_(4)^(+) radical in solution can be detected by

Answer»

FEHLING's solution
Benedict's solution
Schiff's reagent
Nessler's reagent

Answer :4
Discussion
25591.

The presence of Mn in steel produces

Answer»

Elasticity
INCREASES TENSILE strength
Both (a) and (b)
NONE of these

Answer :C
Discussion
25592.

The presence of magnisium is confirmed in the qualitative analysis of the formation of a white crystalline ppt. which is due to

Answer»

`Mg(HCO_(3))_(2)`
`MgNH_(4)PO_(4)`
`MgNH_(4)(HCO_(3))_(3)`
`MgCO_(3)`

SOLUTION :`MgCl_(2)+NH_(4)OH +(NH_(4))_(2)HPO_(4) to underset("WHITE ppt.")(Mg(NH_(4))PO_(4))+2NH_(4)Cl+H_(2)O`
Discussion
25593.

The presence of magnessium is confimed in the qualitative amalysis by the formation of a white crystaline precipitate of :

Answer»

`MG(HCO_(3))_(2)`
`MgNH_(4)PO_(4)`
`MgNH_(4)(HCO_(3))_(3)`
`MgCO_(3)`

Solution :`MgCI_(2) + Na_(2)HPO_(4) + NH_(4)OH rarr underset("White ppt")(Mg(NH_(4))PO_(4) +2NaCI +H_(2)O`
Discussion
25594.

The presence of _________ lowers the activationenergy and provides an alternative path for the reaction.

Answer»

SOLUTION :CATALYST
Discussion
25595.

The presence of ............in the body induces the formation of antibodies.

Answer»

SOLUTION :ANTIGENS
Discussion
25596.

The presence of H_(2)S gas is not identified by

Answer»


`Na_(2)[FE(CN)_(5)(NO)]+NAOH`
`IO_(3)^(-)(aq)+H^(+)(aq)`
`FeCl_(3)(aq)`

Solution :
Discussion
25597.

The presence of electrical charge on colloidal particles is indicated by:

Answer»

electrolysis
dialysis
ELECTROPHORESIS
Tyndall effect.

Solution :The CHARGE on COLLOIDAL PARTICLES is INDICATED by electrophoresis.
Discussion
25598.

The presence of halogen, in an organic compound,is detected by

Answer»

Iodoform test
Silver NITRATE test
BEILSTEIN test
Millon's test

Solution :Halogen are detected by Beilstein's test. In this test, a copper wire is dipped in original solution and heatedin a bunsen burner flame. Freen COLOUR is IMPARTED to the flame, due to the formation of a volatile copper halide. This proves the PRESENCE of halogen.
Discussion
25599.

The presence of colloidal particles of dust in imparts blue colour to the sky. This is due to

Answer»

ABSORPTION of the LIGHT
SCATTERING of the light
Reflection of the light
None of the these

Solution :DUE to scattering of the light. Therefore,`(2)` is correct option.
Discussion
25600.

The presence of carbohydrate is detected chemically by ……………..

Answer»

Xanthoproteic TEST
NINHYDRIN test
MOLISCH's test
Barfoed's test

SOLUTION :Molisch.s test
Discussion