The coagulating power of an electrolyte for arsenious sulphide de

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31.

Which one of the following impurities present in colloidal solution cannot be remove by electrodialysis ?

  • Sodium chloride

  • Potassium sulphate

  • Urea

  • Calcium chloride


32.

The number of moles of lead nitrate needed to coagulate 2 moles of colloidal [AgI]I- is

  • 2

  • 1

  • 1/2

  • 2/3


33.

Plot of log x/m against log p is a straight line inclined at an angle of 45°. When the pressure is 0.5 atm and Freundlich parameter, k is 10, the amount of solute adsorbed per gram of adsorbent will be (log 5 = 0.6990).

  • 1g

  • 2g

  • 3g

  • 5g


34.

On adding 1 mL of solution of 10% NaCl to 10 mL of gold sol in the presence of 0.25 g of starch, the coagulation is just prevented. The gold number of starch is

  • 250

  • 25

  • 2.5

  • 0.25


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35.

Lyophilic sols are more stable than lyophobic sols because the particles :

  • are positively charged

  • are negatively charged

  • are solvated

  • repel each other


36.

Potassium stearate is obtained by the saponification of an oil or fat. It has the formula CH3–(CH2)16 .The molecule has a lyophobic end [CH3] and a lyophilic 'end COO- K+.Potassium stearate is an example for:

  • lyophobic colloid

  • associated colloid or micelle

  • lyophilic colloid

  • multimolecular colloid


37.

On addition of 1 mL solution of 10% NaCl to 10 mL gold solution in the presence of 0.025 g of starch, the coagulation is prevented because starch has the following gold numbers :

  • 25

  • 0.025

  • 0.25

  • 2.5


38.

When a beam of light is passed through a colloidal solution it :

  • is reflected

  • is scattered

  • transmitted

  • absorbed


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39.

The coagulating power of an electrolyte for arsenious sulphide decreases in the order :

  • Na+ > Al3+ > Ba2+

  • PO43- > SO42- > Cl-

  • Cl > SO42- > PO43-

  • Al3+ > Ba2+ > Na+


D.

Al3+ > Ba2+ > Na+

The effective ions of the electrolyte in bringing about coagulation are those which carry charge opposite to that of the colloidal particles and hence, named as coagulating ions. Greater is the valency of the coagulating ion, greater is its power to bring about the coagulation. 

Coagulating power of an electrolyte for arsenious sulphide decreases as Al3+ > Ba2+ > Na+


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40.

Colligative properties are used for the determination of :

  • molar mass

  • equivalent weight

  • arrangement of molecules

  • melting point and boiling point


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