Van't Hoff Factor

Q. What is the van’t Hoff factor when $AlC{l}_3$, is mixed in the solution?

1. 1
2. 2
3. 3
4. 4

Q. Which of the following solutions are isotonic with respect to $0.5M$ $NaCl$ solution having the degree of dissociation = 0.8.

1. $153.9g$ of sucrose is dissolved in $500mL$ of solution
2. $0.3M$ aq. $N{a}_{2}S{O}_4$ solution undergoing $100\%$ ionization
3. $1.8\%$ w/w aq.$NaOH$ solution undergoing $100\%$ ionization
4. $1.2M$ benzoic acid in a solution of benzene where the acid dimerizes to an extent of $50\%$

Q. If $\alpha$ is the degree of dissociation of $N{a}_{2}S{O}_4$ the van't Hoff''s factor $\left(i\right)$ used for calculating the molecular mass is

1. $1+\alpha$
2. $1-\alpha$
3. $1+2\alpha$
4. $1-\alpha$

Q. The degree of dissociation $\left(\alpha \right)$ of a weak electrolyte, $A_x{B}_y$ is related to the van ’t Hoff factor (i) by the expression:

1. $\alpha =\frac{i-1}{(x+y-1)}$
2. $\alpha =\frac{i-1}{(x+y+1)}$
3. $\alpha =\frac{x+y-1}{i-1}$
4. $\alpha =\frac{(x+y+1)}{i-1}$

Q. Which is the correct expression of van't Hoff factor for association of electrolyte?
Here,
n is the number of molecules associate to form n-mer
$\beta$ is the degree of dissociation

1. $i=2+\left[\frac{1}{n}-1\right]\beta$
2. $i=1+[n-1]\beta$
3. $i=1+\left[\frac{1}{n}-1\right]\beta$
4. $i=1+\left[\frac{1}{n}+1\right]\beta$

Q. What is the value of van’t Hoff factor (i) for $60\%$ association of $C{H}_{3}COOH$ in benzene?

1. 0.5
2. 0.4
3. 0.7
4. 0.9

Q.

The Van't Hoff factor calculated from association data is always ________ than calculated from dissociation data.

1. Less

2. More

3. Same

4. More or less

Q. The percentage of pyridine $C_5{H}_{5}N$ that forms pyridinium ion $\left(C_5{H}_5{N}^{+}H\right)$ in a 0.10 M aqueous pyridine solution $(K_b$ for $C_5{H}_{5}N=1.7\times {10}^{-9})$ is

1. 0.77%
2. 1.6%
3. 0.0060%
4. 0.013%

Q. Which one of the following electrolytes has the same value of van't Hoff factor $\left(i\right)$ as that of $K_{4}Fe(CN{)}_6$ (if all are 100% ionised)?

Q.

Van't Hoff factor i can be best described as:

1. 

2. 

3. Less than one in case of dissociation

4. More than one in case of association

Q. Choose the correct statement(s) :
(Assume 100% ionisation)

Q.

The vapour pressure of pure water at 100⁰c is 760mm of Hg while that of dilute solution of urea is 740mm of Hg. Then mass of urea present in 7.60g water is

1. 0.67g

2. 6.7g

3. 7.6g

4. 0.76g

Q. Van’t Hoff factor of $H{g}_{2}C{l}_2$ in its aqueous solution will be $(H{g}_{2}C{l}_2$ is 80% ionized is the solution)

1. 1.6
2. 2.6
3. 3.6
4. 4.6

Q. Match Column I with Column II, where column II represents ‘I’.
$\begin{array}{cc}\text{Column I}& \text{Column II}\\ \text{a.}{K}_4\left[Fe\right(CN{)}_6]& \text{p.}1\\ \text{b.}F{e}_2(S{O}_4{)}_3& \text{q.}1+4\alpha \\ \text{c.}{C}_6{H}_{12}{O}_6& \text{r.}1+\alpha \\ \text{d.}BaC{l}_2& \text{s. Greater than}1\\ & \text{t. Less than}1\end{array}$

1. (a - q ; b - s; c - p; d - s)
2. (a - q, s;b - q, s;c - p; d - s)
3. (a - q, s;b - q, s;c - p, s; d - s)
4. (a - q, s;b - q, s;c - p, s; d - p, s)

Q. Studies on the elevation in boiling point of $Ca(N{O}_3{)}_2$ gives its molar mass to be $131.2\text{g/mol}$. The degree of dissociation of $Ca(N{O}_3{)}_2$ is:

1. $100\%$
2. $75\%$
3. $50\%$
4. $12.5\%$

Q.

Which of the following compounds corresponds Van't Hoff factor to be equal to 2 for dilute solution:

1. 

2. 

3. Sugar

4. 

Q. The extent of adsorption from Langmuir adsorption isotherm is given by
$\frac{x}{m}=\frac{aP}{1+bP}$
The value of a and b are, respectively:

where,
$k_a$ and $k_d$ are rate constant of adsorption and desorption respectively.
$K_1$ is proportionality constant.

1. $\frac{k_a}{k_d}$ and $\frac{k_a}{k_d}$
2. $K_1\frac{k_a}{k_d}$ and $\frac{k_a}{k_d}$
   
3. $K_1\frac{k_a}{k_d}$ and $\frac{k_d}{k_a}$
4. $K_1\frac{k_d}{k_a}$ and $\frac{k_a}{k_d}$

Q.

25.4g of $I_2$ and 14.2g of $C{l}_2$ are made to react completely to yield a mixture of $ICl$ and $IC{l}_3$ .Calculate moles of $ICl$ and $IC{l}_3$ formed.

1. 0.1, 0.1

2. 0.2, 0.2

3. 0.1, 0.2

4. 0.2, 0.1

Q. If $\alpha$ is the degree of dissociation of $N{a}_{2}S{O}_4$ the van't Hoff''s factor $\left(i\right)$ used for calculating the molecular mass is

1. $1+\alpha$
2. $1-\alpha$
3. $1+2\alpha$
4. $1-\alpha$

Q. When 20 g of naphthoic acid $\left(C_{11}{H}_8{O}_2\right)$ is dissolved in 50 g of benzene $(Kf=1.72kgmo{l}^{-1})$, a freezing point depression of 2 K is observed. The Van’t Hoff factor (i) is

1. 0.5
2. 1
3. 2
4. 3

Q. 2 litres of a 1 molar solution of a complex salt $CrC{l}_3.6H_{2}O$ (molar mass $266.5{\text{g mol}}^{-1})$ shows an osmotic pressure of $98.52\text{atm}$. The solution is now treated with 1 litre of $6\text{M}AgN{O}_3$. Which of the following statements is/are correct?

1. Mass of $AgCl$ precipitated is $861\text{g}$
2. The clear solution will show an osmotic pressure of $98.52\text{atm}$
3. The clear solution will show an osmotic pressure of $65.68\text{atm}$
4. 2 moles of $\left[Cr\right(H_{2}O{)}_6](N{O}_3{)}_3$ will be present in the solution

Q. The osmotic pressure of a $0.1\text{M}$ aqueous solution of $MgC{l}_2$ at $300\text{K}$ is $4.92\text{atm}$. What will be the percentage ionisation of the salt?

1. $49\%$
2. $59\%$
3. $79\%$
4. $69\%$

Q. If $\alpha$ is the degree of dissociation of $N{a}_{2}S{O}_4$, the vant Hoff's factor (i) used for calculating the molecular mass is

1. $1+\alpha$
2. $\alpha$
3. $1+2\alpha$
4. $1-2\alpha$

Q. When 9.45 g of $ClC{H}_{2}COOH$ is added to 500 mL of water , its freezing point drops by ${0.5}^{0}C$ . The dissociation constant of $ClC{H}_{2}COOH$ is $x\times {10}^{-3}$ . The value of x is ( Rounded off to the nearest integer ) $[K_{f\left(H_{2}O\right)}=1.86KKgmo{l}^{-1}]$
(JEE MAIN 2021)

Q.

Which one of the following electyrolytes has the same value of van’t Hoff factor (i) as that of $A{l}_2(S{O}_4{)}_3$ (if all are 100% ionized)?

1. $Al(N{O}_3{)}_3$

2. $K_4\left[Fe\right(CN{)}_6]$

3. $K_{2}S{O}_4$

4. $K_3\left[Fe\right(CN{)}_6]$

Q.

A 5.25% solution of a substance is isotonic with a 1.5% solution of urea (molecular mass = 60g/mole) in the same solvent . If the densities of both the solutions are assumed to be equal to 1g/cc, molar mass of substance will be

1. 210.0g/mole
2. 90.0g/mole
3. 115.0g/mole
4. 105.0g/mole

Q.

The ratio of the value of any colligative property for KCl solution to that for sugar solution is nearly:

1. 1

2. 0.5

3. 2.0

4. 3

Q.

Considering complete ionization, Van't Hoff factor of Ca(NO₃)₂ is:

1. 1

2. 2

3. 3

4. 4

Q. For an aqueous solution of sugar, i = ______.

1. $\pm 1$
2. 1
   
3. $<0$
   
4. $>1$

Q.

One mole of a solute A is dissolved in a given volume of a solvent. If solute undergoes association, it's Van't Hoff factor i is expressed as:

1. 

2. 

3. 

4.