JEE Main Chemistry - State of Matter Gaseous and Liquid States
Exam Duration: 60 Mins Total Questions : 30
The minimum pressure required to compress \(500\ dm^3\) of air at 1 bar to \(200\ dm^3\) at \(30^o\ C\) is
- (a)
1 bar
- (b)
2.5 bar
- (c)
5 bar
- (d)
5.8 bar
A student forgot to add the reaction mixture to the round bottomed flask and \(27^oC\) but instead he/she placed the flask on the flame. After a lapse of time, he realised his mistake and using a pyrometer he found the temperature of the flask was \(477^oC\). What fraction of air would have been expelled out?
- (a)
1.1
- (b)
0.8
- (c)
0.65
- (d)
0.6
Which of the following graphs is not a straight line for an ideal gas?
- (a)
V versus T (n and p constant)
- (b)
T versus p (n and V constant)
- (c)
p versus 1 / V (n and T constant)
- (d)
n versus 1 / p (V and T constant)
The SI unit for the quantity \(pV^2T^2/n\) is
- (a)
\(Nm^2\ K\ mol^{-1}\)
- (b)
\(Nm^4\ K\ mol^{-1}\)
- (c)
\(Nm^4\ K^2\ mol^{-1}\)
- (d)
\(N^{-1}m^2\ K^2\ mol^{-1}\)
He atom is two times heavier than a hydrogen molecule. At 298 K, the average kinetic energy of the atom is
- (a)
two times that of a hydrogen
- (b)
same as that of a hydrogen molecule
- (c)
one fourth that of a hydrogen molecule
- (d)
half that of a hydrogen molecule
As the temperature increases, average kinetic energy of molecules increases. What would be the effect of increase of temperature on pressure provided the volume is constant?
- (a)
Increases
- (b)
Decreases
- (c)
Remains same
- (d)
Becomes half
For a monoatomic gas, kinetic energy is E. Its relation with \(V_{rmx}\) velocity is
- (a)
\(v_{rms}=({2E\over m})^{1/2}\)
- (b)
\(v_{rms}=({E\over m})^{1/2}\)
- (c)
\(v_{rms}=({E\over 2m})^{1/2}\)
- (d)
\(v_{rms}=({4E\over 3m})^{1/2}\)
The ratio of root mean square velocity to average velocity of a gas molecule at a particular temperature is
- (a)
1 : 1.086
- (b)
2 : 1.86
- (c)
1.086 : 1
- (d)
2.086 : 1
A gas obeys the equation of state \(p(V-b)=RT\) where, b is a constant. The slope for an isochore will be
- (a)
negative
- (b)
zero
- (c)
\({R\over (V-b)}\)
- (d)
\(R\over P\)
A person living in Shimla observed that cooking food without using pressure cooker takes more time. The reason for this observation is the at high altitude.
- (a)
pressure increases
- (b)
temperature decreases
- (c)
pressure decreases
- (d)
temperature increases
Increase in kinetic energy can overcome intermolecular forces of attraction. How will the viscosity of liquid be affected by the increase in temperature?
- (a)
Increase
- (b)
No effect
- (c)
Decrease
- (d)
No regular pattern wil be followed
Six grams each of the following gases at \(87^oC\) and 750 mm pressure are taken. Which of the following has the least volume?
- (a)
HF
- (b)
HCl
- (c)
HBr
- (d)
HI
Natural hydrogen consists of 80% \(H_2\) and 20% \(D_2\) by mass. The number of ideal diffusion steps required to produce 94.11% \(H_2\) from mixture are
- (a)
12
- (b)
8
- (c)
6
- (d)
4
If excess of \(F_2\ (g)\) reacts at \(150^o\ C\) and 1.0 atm pressure with \(Br_2(g)\), a compound \(BrF_n\) is formed. If 423 mL of \(Br_2(g)\) at the same temperature and pressure produces 4.2 g of \(BrF_n,\) the value of n is \(({Br=80, F=19})\)
- (a)
1
- (b)
3
- (c)
5
- (d)
7
At higher temperature, greater number of molecules have high velocity.
- (a)
kinetic energy of A > kinetic energy of B
- (b)
the number of molecules of methane is four times that of \(O_2\)
- (c)
pressure in flask A < pressure in flask B
- (d)
molecules in flask B are twice more than that in flask A
When an ideal gas undergoes unrestrained expansion, no cooling occurs because the molecules
- (a)
are above inversion temperature
- (b)
collide without loss of energy
- (c)
do work equal to loss in kinetic energy
- (d)
exert no attractive forces on each other.
For two gases A and B with molecular weights \(M_A\) and \(M_B\), it is observed that at temperature T, the average velocity of A is equal to the RMS velocity of A is equal to the RMS velocity of B. At what conditions, the average velocity of A can be made equal to the average velocity of B?
- (a)
A is lowered to a temperature \(T_2={3\pi\over 8T}\)
- (b)
B is lowered to a temperature \(T_2=8T/3\pi\)
- (c)
A is lowered to a temperature \(T_2={8\pi\over 3\pi}\)
- (d)
B is lowered to a temperature \(T_2={3\pi\over 8T}\)
If the most probable speed is represented by mps and fraction of molecules possessing this speed by f, then which option is correct with the increase in temperature?
- (a)
Both mps and f will decrease
- (b)
Both mps and f will increase
- (c)
mps will increase but f will decrease
- (d)
mps will decrease but f will increase
If van der Waals' parameters for gases P,Q,R and S are given as
Gas | a\((time^2-atm/mol^2)\) | b(time/mol) |
P | 4.0 | 0.027 |
Q | 8.0 | 0.030 |
R | 12.0 | 0.027 |
S | 6.0 | 0.024 |
The gas which has the highest Boyle's temperature is
- (a)
P
- (b)
Q
- (c)
R
- (d)
S
At moderate pressure, the compressibility factor of a particular gas is given by \(Z=1+0.34\ p-{170\ p\over T};\) where p is in bar and T is in kelvin. What will be the Boyle's temperature?
- (a)
100 K
- (b)
380 K
- (c)
500 K
- (d)
680 K
When r, p and M represent rate of diffusion, pressure and molecular mass, respectively, then the ratio of the rates of diffusion \((r_A/r_B)\) of two gases A and B is given as
- (a)
\(({p_A\over p_B})^{1/2}({M_A\over M_B})\)
- (b)
\(({p_A\over p_B})({M_A\over M_B})^{1/2}\)
- (c)
\(({p_A\over p_B})^{1/2}({M_B\over M_A})\)
- (d)
\(({p_A\over p_B})({M_A\over M_B})^{1/2}\)
For gaseous state, if most probable speed is denoted by C*, average speed by C and mean square speed by C, then for a large number of molecules, the ratios of these speed are
- (a)
\(C*:\overline C:C=1.225 : 1.128 : 1\)
- (b)
\(C*:\overline C:C=1.128 : 1.225 : 1\)
- (c)
\(C*:\overline C:C=1:1.128 : 1.225\)
- (d)
\(C*:\overline C:C=1 : 1.225 : 1.128\)
If Z is a compressibility factor, van der Waals' equation at low pressure can be written as
- (a)
\(z=1+{RT\over pb}\)
- (b)
\(z=1-{a\over VRT}\)
- (c)
\(z=1-{pb\over RT}\)
- (d)
\(z=1+{pb\over RT}\)
a and b are van der Waals' constants for gases. Chlorine is more easily liquefied then ethane because
- (a)
a and b for \(Cl_2>\)a and b for \(C_2H_6\)
- (b)
a and b for \(Cl_2<\)a and b for \(C_2H_6\)
- (c)
a for \(Cl_2<\) a for \(C_2H_6\) but b for \(Cl_2>b\) for \(C_2H_6\)
- (d)
a for \(Cl_2>\) a for \(C_2H_6\) but b for \(Cl_2 for \(C_2H_6\)
The molecular velocity of any gas is
- (a)
inversely proportional to the square root of temperature
- (b)
inversely proportional to absolute temperature
- (c)
directly proportional to square of temperature
- (d)
directly proportional to square root of temperature
If \(10^{-4} dm^3 \) of water is introduced into a \(1.0 dm^3\) flask at 300 K, how many moles of water are in the vapour phase when equilibrium is established? [Given, vapour pressure of \(H_2O\) at 300 K is 3170 Pa, R = 8.314 \(JK^{-1}\ mol^{-1}\)]
- (a)
\(5.56\times 10^{-3}\ mol\)
- (b)
\(1.53\times 10^{-2}\ mol\)
- (c)
\(4.46\times 10^{-2}\ mol\)
- (d)
\(1.27\times 10^{-3}\ mol\)
Equal masses of methane and oxygen are mixed in an empty container at \(25^oC.\) The fraction of the pressure exerted by oxygen is
- (a)
\(2\over 3\)
- (b)
\({1\over 3}\times {273\over 298}\)
- (c)
\(1\over 3\)
- (d)
\(1\over 2\)
If helium and methane are allowed to diffuse out of the container under the similar conditions of temperature and pressure, then ratio of rate of diffusion of helium to methane is
- (a)
2.0
- (b)
1.0
- (c)
0.5
- (d)
4.0
As the temperature is raised from \(20^oC\) to \(40^oC\), the average kinetic energy of neon atoms changes by a factor of which of the following?
- (a)
1/2
- (b)
\(\sqrt{3113/293}\)
- (c)
\(313/293\)
- (d)
2