The protective power of the lyophilic colloids is expressed in terms of gold number a term introduced by Zsigmondy. Gold number is the number of milligrams of the protective colloid which prevent the coagulation of $10$ ml of red gold sol. When $1$ ml of a $10$ percent solution of sodium chloride is added to it. Thus, smaller the gold number of lyophilic colloid, the greater is the protective power.
On addition of one mL of solution of $10 %$ $N a C l$ to $10$ mL of red gold sol in presence of $0.025$ g of starch, the coagulation is just prevented. The gold number of starch is :

0.025

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0.25

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2.5

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25

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Solution

The correct option is C $25$
Gold number is the number of milligrams of the protective colloid which prevent the coagulation of $10$ ml of red gold sol. When $1$ ml of a $10$ percent solution of sodium chloride is added to it.
Here, milligrams of starch used $= 25$ .
Therefore, Gold number is $= 25$ (as $0.025 g m = 25 m i l l i g r a m$ ).

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The protective power of the lyophilic colloids is expressed in terms of gold number, a term introduced by Zsigmondy. The gold number is the number of milligrams of the protective colloid that prevents the coagulation of

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1 m L

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Which of the following statement(s) is/are correct

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