Coagulation

Q.

What does hardy schulze rule state?

Q.

Define ionization enthalpy? What is its unit? What is the principle of its measurement?

Q. Arrange the following in increasing flocculating power for coagulation of positive sol.$\left[Fe\right(CN{)}_6{]}^{-4},P{O}_4^{-3},S{O}_4^{-2},C{l}^{-}$

1. $P{O}_4^{-3},S{O}_4^{-2},C{l}^{-}\left[Fe\right(CN{)}_6{]}^{-4}$
   
2. $C{L}^{-},S{O}_4^{-2},P{O}_4^{-3},\left[Fe\right(CN{)}_6{]}^{-4}$
   
3. $\left[Fe\right(CN{)}_6{]}^{-4},P{O}_4^{-3},S{O}_4^{-2},C{l}^{-}$
   
4. $S{O}_4^{-2},P{O}_4^{-3},C{l}^{-},\left[Fe\right(CN{)}_6{]}^{-4}$

Q.

Explain hardy-schulze law with examples

Q. what is protection of colloids?what is bredigs arc method and what are associated colloids?

Q.

How are clouds formed?How does artificial rain occur when electrified salt is sprayed over clouds?

Q.

What is the hardy Schulze rule?

Q. For the strong electrolytes NaOH, NaCl and $BaC{l}_2,$ the molar ionic conductances at infinite dilution are $248.1\times {10}^{-4},126.5\times {10}^{-4}and280.0\times {10}^{-4}S{m}^{2}mo{l}^{-1},$ respectively. Calculate ${\Lambda }_m^{\circ }\text{for}Ba(OH{)}_2$:

1. $523.2\times {10}^{-4}S{m}^{2}mo{l}^{-1}$
2. $550.4\times {10}^{-4}S{m}^{2}mo{l}^{-1}$
3. $600.5\times {10}^{-4}S{m}^{2}mo{l}^{-1}$
4. $500.0\times {10}^{-4}S{m}^{2}mo{l}^{-1}$

Q. According to Kohlrausch law, the limiting value of molar conductivity of an strong electrolyte $A_{2}B$ is given by:

1. ${\lambda }_{A^{+}}^0+{\lambda }_{B^{2-}}^0$
2. $\frac{1}{2}{\lambda }_{A^{+}}^0+{\lambda }_{B^{2-}}^0$
3. ${\lambda }_{A^{+}}^0+2{\lambda }_{B^{2-}}^0$
4. $2{\lambda }_{A^{+}}^0+{\lambda }_{B^{2-}}^0$

Q. $80.0\text{g}$ salt of weak base and strong acid $XY$, is dissolved in water and formed $2$ liter of aqueous solution. The $pH$ of the resultant solution was found to be $5$ at $298\text{K}$. If $XY$ forms $CsCl$ type crystal having $r_{X^{+}}\left(\text{radius of}{X}^{+}\right)=1.6A^{\circ }$ and $r_{Y^{+}}\left(\text{radius of}{Y}^{+}\right)=1.864A{}^{\circ }$, then select the correct statement (s).
(Given : $K_b\left(XOH\right)=4\times {10}^{-5};N_A=6\times {10}^{23}$)

1. Molar mass of salt is $100\text{g/mol}$
2. $\%$ Degree of dissociation of salt is $0.25$
3. Edge length of $XY$ is $4A^{\circ }$
4. Density of solid salt $XY$ is $2$ in $\text{g/cc}$

Q.

The coagulation of 100 ml of colloidal solution of gold is completely prevented by addition of 0.25 g of a substance “X” to it before adding 1 ml of 10% NaCl solution. The gold number of “X” is

1. 0.25
2. 2.5
3. 25
4. 250

Q.

Which is not a process of purification of colloidal Solutions?

1. Ultra centrifugation

2. Ultrafiltration

3. Dialysis

4. Peptization

Q. Ferric chloride is applied to stop bleeding because

1. Fe³⁺ ions coagulate positively charged blood solution
2. Cl^– ions coagulate positively charged blood solution
3. Cl^– ions coagulate negatively charged blood solution
4. Fe³⁺ ions coagulate negatively charged blood solution

Q.

As per the Hardy-Schulze formulation, the flocculation values of the following for ferric hydroxide sol are in the order:

1. ${\mathrm{AlCl}}_3>{\mathrm{K}}_3\left[\mathrm{Fe}\right(\mathrm{CN}\left)6\right]>{\mathrm{K}}_2{\mathrm{CrO}}_4>\mathrm{KBr}={\mathrm{KNO}}_3$

2. ${\mathrm{K}}_3[\mathrm{Fe}{\left(\mathrm{CN}\right)}_6]<{\mathrm{K}}_2{\mathrm{CrO}}_4<{\mathrm{AlCl}}_3<\mathrm{KBr}<{\mathrm{KNO}}_3$

3. ${\mathrm{K}}_3[\mathrm{Fe}{\left(\mathrm{CN}\right)}_6]<{\mathrm{K}}_2{\mathrm{CrO}}_4<\mathrm{KBr}={\mathrm{KNO}}_3={\mathrm{AlCl}}_3$

4. ${\mathrm{K}}_3[\mathrm{Fe}{\left(\mathrm{CN}\right)}_6]>{\mathrm{AlCl}}_3>{\mathrm{K}}_2{\mathrm{CrO}}_4>\mathrm{KBr}>{\mathrm{KNO}}_3$

Q. Which of the following will have the highest coagulating power for the colloid $Fe(OH{)}_3$?

1. $P{O}_4^{3-}$
2. $S{O}_4^{2-}$
3. $C{a}^{2+}$
4. $A{l}^{3+}$

Q. Which of the following is not an example of lyophobic colloids?

1. Gold solution
2. Sulphur solution
3. $NaCl$ solution
4. Blood

Q. Under the influence of an electric field, the particles in a sol migrate towards the cathode. The coagulation of the same sol is studied using $NaCl,N{a}_{2}S{O}_4$ and $N{a}_{3}P{O}_4$ solutions. The coagulating values will be highest for:

1. $NaCl$
2. $N{a}_{2}S{O}_4$
3. $N{a}_{3}P{O}_4$
4. Same for all

Q. The molar conductivities of $NaOAc$ and $HCl$ at infinite dilution in water at ${25}^{\circ }C$ are $91.0$ and $426.2Sc{m}^{2}mo{l}^{-1}$ respectively. To calculate the limiting molar conductivity of $HOAc$ at same temperature, the additional value required is:

1. ${\Lambda }_{H_{2}O}^0$
2. ${\Lambda }_{KCl}^0$
3. ${\Lambda }_{NaOH}^0$
4. ${\Lambda }_{NaCl}^0$

Q. Molar conductivity $\left(\Lambda m\right)$ of an aqueous solution of sodium stearate, which behaves as a strong electrolyte, is
recorded at varying concentrations (c) of sodium stearate. Which one of the following plots provides the
correct representation of micelle formation in the solution?
(critical micelle concentration (CMC) is marked with an arrow in the figures)

1. 
2. 
3. 
4. 

Q.

Colloidal solutions of gold prepared by different methods are of different colors due to _______.

1. Variable valency of gold

2. Different sizes of gold particles

3. Different concentrations of gold particles

4. Presence of impurities produced by different methods

Q. Which of the following statement is incorrect ?

${\Lambda }_m$ - Molar conductivity
${\Lambda }_m^0$ - Limiting molar conductivity
$C$ - concentration of electrolyte

1. Molar conductivity of a strong electrolyte increases with dilution
2. Variation of molar conductivity for strong electrolyte is given by,
   ${\Lambda }_m={\Lambda }_m^0+\sqrt{C}$
3. Molar conductivity of a weak electrolyte increases with dilution
4. ${\Lambda }_m^0$ for a strong electrolyte can be found from the plot of ${\Lambda }_{m}vs\sqrt{C}$by extrapolation of ${\Lambda }_m$ to zero concentration

Q. For the coagulation of 50 ml of ferric hydroxide sol, 10 ml of 0.5 M KCl is required. What is the coagulation value of $KCl$?

1. 5
2. 10
3. 100
4. None of these

Q. Which of the following represent the plot of ${\Lambda }_m$ vs $\sqrt{C}$ for a strong electrolyte ($KCl$)?

${\Lambda }_m$ - Molar conductivity
$C$ - concentration of electrolyte

1. 
2. 
3. 
4. 

Q. Which of the following statement is correct for a weak electrolytic solution?
${\Lambda }_m$ - Molar conductivity
${\Lambda }_m^0$ - Limiting molar conductivity
$C$ - concentration of electrolyte

1. ${\Lambda }_m^0$ cannot be found by extrapolation of ${\Lambda }_m$ to zero concentration.
2. On dilution, molar conductivity increases due to decrease in ion-ion forces of attraction.
3. Plot of ${\Lambda }_m^{0}vs\sqrt{C}$ will give a straight line.
4. ${\Lambda }_m^0$ can be found by extrapolation of ${\Lambda }_m$ to zero concentration.

Q. Aluminium hydroxide forms a positively charged sol. Which of the following ionic substances should be most effective in coagulating the sol?

1. $NaCl$
2. $F{e}_2(S{O}_4{)}_3$
3. $CaC{l}_2$
4. $K_{3}P{O}_4$

Q.

A sol has positively charged colloidal particles. Which of the following solutions is required in lowest concentration for coagulation -

1. Na2SO4
2. NaCl
3. K4[Fe(CN)6]
4. ZnCl2

Q.

Lyophilic colloids that shows the property of protecting lyophobic colloids are also called as:

1. Protective colloids

2. Non-Protective colloids

3. Both protective and non protective

4. Associated colloids

Q.

The ability of an ion to bring about coagulation of a given colloid depends

upon

1. The sign of its charge

2. Its size

3. The magnitude of its charge only

4. Both the magnitude and the sign of its charge

Q. What is coagulation? Explain the Hardy and Schulze rules.

Q.

A negatively charged suspension of clay in water will need for precipitation the minimum amount of

1. Aluminium chloride
2. Potassium sulphate
3. Hydrochloric acid
4. Sodium hydroxide