Van der Waal's Forces

Q.

The degree of freedom for tri-atomic gas is

1. $6$

2. $4$

3. $2$

4. $8$

Q. At high pressure, van der Waal's equation for one mole of the gas becomes:

1. $PV=RT+\frac{a}{V}$
2. $PV=RT-\frac{a}{V}$
3. $PV=RT$
4. $PV=RT+Pb$

Q.

A cylinder containing an ideal gas $\left(0.1\mathrm{mol}\mathrm{of}1.0{\mathrm{dm}}^3\right)$ is in thermal equilibrium with a large volume of $0.5\mathrm{Molal}$ aqueous solution of ethylene glycol at its freezing point. If the stoppers ${\mathrm{S}}_1$ and ${\mathrm{S}}_2$ (as shown in the figure) suddenly withdrawn, the volume of the gas in $\mathrm{Liters}$ after equilibrium is achieved will be:

(Given, ${\mathrm{K}}_{\mathrm{f}}\left(\mathrm{water}\right)=2.0\mathrm{K}{\mathrm{kgmol}}^{-1},\mathrm{R}=0.08{\mathrm{dm}}^3\mathrm{atm}{\mathrm{K}}^{-1}{\mathrm{mol}}^{-1}$)

Q. The constant '$a$' in van der Waals' equation is maximum in:

1. $He$
2. $O_2$
3. $N{H}_3$
4. $H_2$

Q.

What are dipole-dipole forces?

Q. For compressibility factor, Z, which of the following is /are correct?

1. For most of the real gases Z decreases with P at the lower pressure
2. For most of the real gases Z increases with P at the higher pressure
3. All of the above statements are correct
4. For $H_2$ (g) and $He\left(g\right)$ Z increases with P at all the pressure & at room temperature

Q. Arrange the following in the decreasing order of their van der Waals constant ${}^{\prime }{a}^{\prime }$ values:
$H_{2}O,C{O}_2,Ar$

1. $Ar>H_{2}O>C{O}_2$
2. $H_{2}O>C{O}_2>Ar$
3. $Ar=H_{2}O=C{O}_2$
4. $H_{2}O>Ar>C{O}_2$

Q. The correction factor ‘a’ to the ideal gas equation corresponds to:

1. Volume of the gas molecules
2. Electric field present between the gas molecules
3. Density of the gas molecules
4. Forces of attraction between the gas molecules

Q. The compressibility factor for a real gas is expressed by, $z=1+\frac{BP}{RT}$. The value of B at 500 K and 600 bar is 0.0169 L/mol. Find the molar volume of the gas

1. 0.1 L
2. $9\times {10}^{-5}L$
3. $8.62\times {10}^{-2}L/mol$
4. 1.65 L

Q. At high temperature and low pressure, the van der Waals' equation is reduced to:

1. $(P+\frac{a}{V^2})V=RT$
2. $P(V-b)=RT$
3. $(P+\frac{a}{V^2})(V-b)=RT$
4. $PV=RT$

Q. Calculate the pressure exerted by one mole of $C{O}_2$ gas at 273 K if the van der Waal's constant, $a=3.592d{m}^{6}atmmo{l}^{-2}$. Assume that the volume occupied by $C{O}_2$ molecules is negligible.

1. $0.9922atm$
   
2. $1.9922atm$
3. $9.9222atm$
4. $0.1922atm$

Q. 'a' and 'b' are van der Waals' constants for gases. Chlorine is more easily liquefied than ethane because

1. a and b for $C{l}_2>a$ and b for $C_2{H}_6$
2. a and b for $C{l}_2<a$ and b for $C_2{H}_6$
3. a for $C{l}_2>a$ for $C_2{H}_6$ but b for $C{l}_2>b$ for $C_2{H}_6$
4. a for $C{l}_2>a$ for $C_2{H}_6$ but b for $C{l}_2<b$ for $C_2{H}_6$

Q. The van der Waals' equation for $0.5\text{mol}$ gas is:

1. $(P+\frac{a}{4V^2})\left(\frac{V-b}{2}\right)=\frac{3RT}{2}$
2. $(P+\frac{a}{4V^2})(2V-b)=RT$
3. $(P+\frac{a}{4V^2})(2V-4b)=RT$
4. $(P+\frac{a}{4V^2})=\frac{2RT}{2(V-b)}$

Q.

The term that corrects for the attractive forces present in a real gas in the Van der Waals equation is _____.

1. 

2. 

3. 

4. 

Q. For one mole of a gas, under critical conditions, the compressibility factor is:

1. $\frac{8}{3}$
2. 1
3. $\frac{1}{4}$
4. $\frac{3}{8}$

Q. Which of the following has the highest melting point?

1. $F_2$
2. $C{l}_2$
3. $B{r}_2$
4. $I_2$

Q. The reduced temperature for benzene is 0.7277 and its reduced volume is 0.40. Calculate the reduced pressure of benzene.

1. $40.358$
2. $30.358$
3. $20.358$
4. $10.358$

Q.

Define London forces

Q. Find the temperature ($\text{in K}$) at which 3 moles of $S{O}_2$ will occupy a volume of $10\text{L}$ at a pressure of $15\text{atm}$.
[ $a=6.71{\text{atm litre}}^2{\text{mol}}^{-2}$; $b=0.0564{\text{litre mol}}^{-1}$]

Q. In van der Waals' equation of state for a non-ideal gas, the term that accounts for intermolecular forces is:

1. $RT$
2. $b$
3. $\frac{a}{V^2}$
4. $(RT{)}^{-1}$

Q. Calculate pressure exerted by 1 mole of a van der Waal gas at a temperature of $\frac{8}{0.0821}K$ in a $\frac{1}{2}L$ container, if the volume of the molecule is assumed to be negligible and van der Waal's constant $a=2{\text{atm L}}^2{\text{mol}}^{-2}$

Q. Statement–1: The value of the van der Waals constant ‘a’ is larger for $N{H}_3$ than $P{H}_3$.
Statement–2: Hydrogen bonding is present in $N{H}_3$

1. Statement-1 is True, Statement-2 is True; Statement-2 is NOT a correct explanation for Statement-1
2. Statement-1 is True, Statement-2 is True; Statement-2 is a correct explanation for Statement-1
3. Statement-1 is True, Statement-2 is False
4. Statement-1 is False, Statement-2 is True

Q.

What is an ideal gas? Explain.

Q. Calculate the temperature of the gas (in kelvin) if it obeys van der Waals' equation from the following data. A flask of $2.5\text{L}$ contains $10\text{mol}$ of a gas under $50\text{atm}$. Given $(a=5.46{\text{atm L}}^2{\text{mol}}^{-2},b=0.031{\text{L mol}}^{-1})$.

Q. Read the following statement and explanation and choose the correct option.
Assertion : The value of van der Waals' constant 'a' is larger for ammonia than for nitrogen.
Reason : Hydrogen bonding is present in ammonia.

1. Both assertion and reason are correct, and reason is the correct explantion of the assertion.
2. Both assertion and reason are correct.
3. Both assertion and reason are correct, but reason is not the correct explantion of the assertion.
4. Both assertion and reason are incorrect.

Q. 36. What is meant by virial coefficient of real gas?

Q.

The weakest interaction among the following is _____.

1. Metallic

2. Ionic

3. Van der Waal

4. Covalent

Q. Which one of the following has the highest boiling point?

1. $Kr$
2. $Xe$
3. $He$
4. $Ne$

Q. 14(L)Consider the following statements:I The pressure of moist gas is more than that ofdry gas under identical condition.Critical temperature is the highest temperatureat which liquid and vapour coexistAt constant temperature, PV vs P (Ppressure and V = volume) plot for real gaseswill be a straight line at very high pressure.28. 10The correct statement(s) is/are(2) Only \vert & II)(1) Only II & IlII)(3) Only I & Il

Q. Calculate the pressure exerted by one mole of $C{O}_2$ gas at 273 K if the van der Waal's constant, $a=3.592d{m}^{6}atmmo{l}^{-2}$. Assume that the volume occupied by $C{O}_2$ molecules is negligible.

1. $0.9922atm$
   
2. $1.9922atm$
3. $9.9222atm$
4. $0.1922atm$