Multiple Choice QuestionsThe cooling in refrigerator is due to :
the reaction of the refrigerator gas
the expansion of ice
the expansion of the gas in the refrigerator
the work of the compressor
C.
the expansion of the gas in the refrigerator
This is based on Joule-Thomson effect.
A precipitate of AgCl is formed when equal volumes of the following are mixed :
[Ksp for AgCl = 10-10]
10-4 M AgNO3 and 10-7 M HCl
10-5 M AgNO3 and 10-6 M HCl
10-5 M AgNO3 and 10-4 M HCl
10-6 M AgNO3 and 10-6 M HCl
B.
10-5 M AgNO3 and 10-6 M HCl
For the precipitation of an electrolyte, it is necessary that the ionic product must exceed its solubility product. A precipitate of AgCl is formed when equal volumes of 10-5 M AgNO3 and 10-5 M HCl are mixed, because ionic product will be 10-9 which is greater than Ksp (10-10).
Pick out the incorrect statement from the following :
sp hybrid orbitals are equivalent and are at an angle of 180° with each other
sp2 hybrid orbitals are equivalent and bond angle between any two of them is 120°
sp3d2 hybrid orbitals are equivalent and are oriented towards corners of a regular octahedron
dsp2 hybrid orbitals are equivalent with a bond angle of 90° between the two atoms
D.
dsp2 hybrid orbitals are equivalent with a bond angle of 90° between the two atoms
Angle between any two dsp2 hybrid orbitals can be 90° or 180°
An evacuated glass vessel weighs 50 g when empty, 144.0 g when filled with a liquid of density 0.47 g mL-1 and 50.5 g when filled with an ideal gas at 760 mm Hg and 300 K. The molar mass of the ideal gas is :
[R = 0.0821 L atm K-1 mol-1]
61.575
130.98
123.75
47.87
A.
61.575
Weight of empty glass vessel = 50 g
Weight of glass vessel filled with liquid = 144.0 g
Weight of liquid = 144- 50 = 94g
Density of liquid= 0.47 gmL-1
Volume of liquid = = 200mL = 0.2L
Mass of glass vessel filled with gas= 50.5 g
Mass of gas (m) = 50.5- 50 = 0.5 g
By using ideal gas equation ,
pV = RT
where , p= 760 mm, Hg= 1atm ,
V = 0.2 L , T = 300K ,
and R = 0.0821 L atm K-1 mol-1
Molar mass (M) =
=
= 61.575g mol-1
In an exothermic equilibrium ,
A + 3B AB3
all the reactants and products are in gaseous state. The formation of AB3 is favoured at :
low temperature and low pressure
low temperature and high pressure
high temperature and high pressure
high temperature and low pressure
B.
low temperature and high pressure
The given reaction is exothermic (H < 0) and accompanied by decrease in the number of moles. Hence, it will be favoured by low temperature and high pressure.
A bivalent metal has an equivalent mass of 32. The molecular mass of the metal nitrate is :
182
168
192
188
D.
188
Atomic mass of the metal = 32 x 2 = 64
Formula of metal nitrate= M(NO3)2
Molecular mass = 64 + (14 + 3 x 16) x 2 = 188
20 mL of 0.5 N HCl and 35 mL of 0.1 N NaOH are mixed. The resulting solution will :
be neutral
be basic
turn phenolphthalein solution pink
turn methyl orange red
C.
turn phenolphthalein solution pink
For 20 ml of 0.5 N HCl
N1V1 = 0.5 x 20 = 10
For 35 ml of 0.1 NaOH
N2V2 = 0.1x 35= 3.5
N1V1 > N2V2
So!ution will be acidic in nature.
Due to acidic nature of solution, the colour of phenolphthalein becomes pink.
The line spectrum of He+ ion will resemble that of :
hydrogen atom
Li+ ion
helium atom
lithium atom
A.
hydrogen atom
As hydrogen atom and He+ ion both have only one electron, hence the line spectrum of both will resemble.
A body of mass x kg is moving with a velocity of 100 ms-1. Its de-Broglie wavelength is 6.62 x 10-35 m. Hence, x is :
[h = 6.62 x 10-34Js]
0.1 Kg
0.25 Kg
0.15 Kg
0.2 Kg
A.
0.1 Kg
=
m =
= 0.1 Kg
0.5 mole of each of H2 , SO2 and CH4 are kept in a container. A hole was made in the container . After 3h , the order of partial pressures in the container will be :
pSO2 > pH2 > pCH4
pSO2 > PCH4 > pH2
pH2 > pSO2 > pCH4
pH2 > pCH4 > pSO2
B.
pSO2 > PCH4 > pH2
Rate of diffusion
Order of diffusion H2 > CH4 > SO2
and amount left is in the order :
SO2 > CH4 > H2
Hence, order of partial pressure is
pSO2 > pCH4 > pH2
