Liquefaction of Gases and Critical Constants

Q.

I always speak the truth (correct the sentence)

Q.

For a real gas (mol. mass = 60 ), if density at critical point is 0.80 $\frac{g}{c{m}^3}$ and its $T_c=\frac{4\times {10}^5}{821}K$.Find the Van der Waals constant “a”(in $atm{L}^{2}mo{l}^{-2}$ ) .

1. 0.3375

2. 3.375

3. 0.025

4. 1.68

Q.

Consider the following statements. The Van der Walls parameters are given as:

Select the correct alternates.

1. A alone

2. A and B

3. A, B and C

4. B and C

Q.

Calculate the volume occupied by 16 gram $O_2$ at 300 K and 8.31 Mpa if $\frac{P_{c}V}{R{T}_c}=\frac{3}{8}and\frac{P_r{V}_r}{T_r}=2.21⟮:R=8.314\frac{Mpa}{K-mol}⟯$

1. 124.31 lit

2. 248.62 L

3. 124.31 mL

4. 248.62 mL

Q. The state of a gas can be described by quoting the relationship between ________.

1. Pressure, volume, temperature, amount
2. Pressure, volume, temperature
3. Amount, volume, temperature
4. Temperature, amount, pressure

Q. van der Waals' constants of two gases $X$ and $Y$ are as given:
$\begin{array}{ccc}& a\left(L^{2}atm{\text{mol}}^{-2}\right)& b\left({\text{L mol}}^{-1}\right)\\ \text{Gas}X& 5.6& 0.065\\ \text{Gas}Y& 5.1& 0.012\end{array}$
Which option is true?

1. $T_c\left(X\right)>T_c\left(Y\right)$
2. $T_c\left(X\right)=T_c\left(Y\right)$
3. $V_c\left(X\right)>V_c\left(Y\right)$
4. $V_c\left(Y\right)>V_c\left(X\right)$

Q. 26. What is the combination ratio of nitrogen is to oxygen

Q.

Liquification of gaseous substances whose critical temperatures are below room temperature requires ____.

1. High pressure and lowering of temperature (below $T_C$).

2. Low pressure and raising of temperature (above $T_C$).

3. High pressure and raising of temperature (above $T_C$).

4. Low pressure and lowering of temperature (below $T_C$).

Q. Given van der Waals constant for $N{H}_3,H_2,O_2$ and $C{O}_2$ are respectively $4.17,0.244,1.36$ and $3.59$, which one of the following gases is most easily liquefied?

1. $O_2$
2. $N{H}_3$
3. $H_2$
4. $C{O}_2$

Q. The relationship between $P_C,V_C$ and $T_C$ is

1. $P_C{V}_C=R{T}_C$
2. $P_C{V}_C=3R{T}_C$
3. $P_C{V}_C=\frac{3}{5}R{T}_C$
4. $P_C{V}_C=\frac{3}{8}R{T}_C$

Q. 65.What is an dark matter do truly it exist

Q.

The van der Waals' parameters for gases W, X, Y and Z are

$\begin{array}{ccc}Gas& a(litr{e}^2-atom/mo{l}^2)& b\left(litre/mol\right)\\ W& 4.0& 0.027\\ X& 8.0& 0.030\\ Y& 6.0& 0.032\\ Z& 12.0& 0.027\end{array}$

Which one of these gases has the highest critical temperature?

1. W

2. X

3. Y

4. Z

Q. Explain why pure liquids and solids can be ignored while writing the equilibrium constant expression?

Q. What is the correct increasing order of a gas being liquifiable?

1. $H_2<N_2<C{H}_4<C{O}_2$
2. $H_2<C{O}_2<C{H}_4<N_2$
3. $C{O}_2<C{H}_4<N_4<H_2$
4. $C{O}_2<C{H}_4<H_2<N_2$

Q. For three different gases values of Van der Waals' constant ${}^{\prime }{a}^{\prime }$ and ${}^{\prime }{b}^{\prime }$ are given. What is the correct order of liquefaction of gases?

Gases	$a$	$b$
$X_2$	$1.3$	$0.090$
$Y_2$	$4.1$	$0.023$
$Z_2$	$2.2$	$0.075$

1. $X_2>Y_2>Z_2$
2. $Y_2>Z_2>X_2$
3. $Z_2>Y_2>X_2$
4. $X_2>Z_2>Y_2$

Q. Atmospheric pressures recorded in different cities are as follows:

$\begin{array}{ccccc}Cities& Mussorie& Bangalore& Delhi& Goa\\ Pin\left(N/m^2\right)& 1.01\times {10}^5& 1.2\times {10}^5& 1.02\times {10}^5& 1.21\times {10}^5\end{array}$

Consider the above data and mark the place at which liquid will boil first.

1. Mussorie
2. Bangalore
3. Delhi
4. Goa

Q. Given below are the critical temperatures of a few gases. When the gases are started cooling, which gas will liquefy first and which will liquefy in the end?

Gas	$T_C/K$
$N_2$	$126.0$
$C{O}_2$	$304.10$
$N{H}_3$	$405.5$
$O_2$	$154.3$

1. $N_2$ will liquefy first and $N{H}_3$ at last
2. $N{H}_3$ will liquefy first and $C{O}_2$ at last
3. $N{H}_3$ will liquefy first and $N_2$ at last
4. $C{O}_2$ will liquefy first and $N{H}_3$ at last

Q. A gas can be liquified by pressure alone only, when its temperature is ___________ its critical temperature.

1. equal to or higher than
2. more than
3. less than or equal to
4. less than

Q. Critical temperature and critical pressure values of four gases are given

$\begin{array}{ccc}\text{Gas}& \text{C. Temp (K)}& \text{C. Pressure (atm)}\\ P& 5.1& 2.2\\ Q& 33& 13\\ R& 126& 34\\ S& 135& 40\end{array}$

Which of the gas/gases cannot be liquefied at a temperature of 100 K and a pressure of 50 atmospheres?

1. S only
2. P only
3. R and S
4. P and Q

Q. If $\frac{P}{P_c}=x$ (reduced pressure), $\frac{V}{V_c}=y$ (reduced volume) and $\frac{T}{T_c}=z$ (reduced temperature), then,

1. $(x-\frac{3}{y^2})(3y-1)=8z$
2. $(x+\frac{3}{y^2})(y-1)=z$
3. $(x-\frac{3}{y^2})(3y+1)=8z$
4. $(x+\frac{3}{y^2})(3y-1)=8z$

Q. If the van der waals parameters of two gases are given as:
$a-d{m}^{6}barmo{l}^{-2}b-d{m}^{3}barmo{l}^{-1}$
$$\begin{array}{cc}GasA-6.5& 0.056\\ GasB-18.0& 0.011\end{array}$$
Then which of the above statements is / are correct?

1. Critical presssure of A< critical pressure of B.
2. Critical temperature of A< critical temperature of B.
3. Both a and b
4. None of the above

Q. What percent of a sample of nitrogen must be allowed to escaped if its temperature , preesure and volume are to be changed from 220 degree c , 3atm, 1.00litre respectively?

Q.

The ratio of Boyle's temperature and critical temperature for a gas is:

1. $\frac{8}{27}$

2. $\frac{27}{8}$

3. $\frac{1}{2}$

4. $\frac{2}{1}$

Q. The temperature below which a gas must be cooled before it can be liquefied by compression is called as .

1. Curie temperature
2. Critical temperature
3. Boyle's temperature

Q. The volume of gases obtained at the anode at STP ($1$ bar and $298K$) when $2$ faraday of electricity is passed is

1. $67.2$ litres
2. $68.1$ litres
3. $73.2$ litres
4. $74.1$ litres

Q. Select the correct statement as critical point is approached:

1. The density of $C{O}_2\left(l\right)$ increases and that of $C{O}_2\left(g\right)$ decreases and at $T=T_c$ densities are equal
2. The density of $C{O}_2\left(l\right)$ decreases and that of $C{O}_2\left(g\right)$ increases and at $T=T_c$ densities are equal
3. The density of both $C{O}_2\left(l\right)$ and $C{O}_2\left(g\right)$ increase
4. The density of both $C{O}_2\left(l\right)$ and $C{O}_2\left(g\right)$ decrease

Q.

Consider the following statements.

I. Gaseous substances whose critical temperatures are above room temperatures can be liquefied by applying sufficient pressure to the gas.

II. Gaseous substances whose critical temperatures are below room temperature can be liquefied by the application of pressure and lowering of temperature below $T_c$.

Select the correct alternate.

1. I

2. II

3. Both (I) and (II) statements are correct.

4. Neither (I) nor (II) is correct.

Q. Gas $A$ can be liquefied at room temperature by applying pressure but gas $B$ cannot. This reflects.

1. critical temperature of $B$ is less than that of $A$
2. critical temperature of $B$ is greater than that of $A$
3. $A$ and $B$ have critical temperature greater than room temperature
4. critical temperatures of both are equal

Q.

Explain, why an organic liquid vaporises at a temperature below its boiling point in its steam distillation?

Q.

Which of the following statements on critical constants of gases are correct?

I : Larger the $\frac{T_c}{P_c}$ value of a gas, larger would be the excluded volume.

II : Critical temperature ($T_c$) of a gas is greater than its Boyle's temperature ($T_B$).

III : At the critical point in the Van der Walls gas isotherm.

$⟮\frac{dP}{d{V}_m}⟯T_c=0$

1. I and II

2. I and III

3. II and III

4. I, II and III