Gold Number

Q. The protecting power of lyophilic colloidal sol is expressed in terms of

1. Coagulation value
2. CMC
3. Oxidation number
4. Gold number

Q. Gold number of protective colloids $A,B,C\text{and}D$ are $0.50,0.01,0.10$ and $0.005$ respectively. The correct order of their protective power is:

1. $D<A<C<B$
2. $C<B<D<A$
3. $A<C<B<D$
4. $B<D<A<C$

Q. 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 milligram of the protective colloid which prevents the coagulation of $10\text{mL}$ of red gold sol. When $1\text{mL}$ of a $10\%$ solution of sodium chlorideis 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 $10\%NaCl$ to $10\text{mL}$ of red gold sol in presence of $0.025\text{g}$ of starch, the coagulation is just prevented. The gold number of starch is:

1. $2.5$
2. $0.25$
3. $0.025$
4. $25$

Q. 0.25 g lyophilic colloid is added to 100 ml gold solution to prevent the coagulation on adding 1 ml 10% NaCl solution. What will be gold number of lyophilic colloid?

Q.

The gold numbers of protective colloids A, B, C and D are 0.04, 0.004, 10 and 40 respectively. The protective powers of A, B, C and D are in the order:

1. A > B > C > D

2. B > A > C > D

3. D > C > A > B

4. D > C > B > A

Q. The coagulation of $10{\text{cm}}^3$ of gold sol by $1\text{mL}$ 10% $NaCl$ solution is completely prevented by addition of $0.025\text{g}$ of starch to it. The gold number of starch is:

Q. 1.82 g of a metal requires 32.5 ml of 1 N HCL to dissolve it. What is the equivalent weight of metal?

Q. Lyophilic colloidal sols are much more stable than lyophobic colloidal sols. This is due to the extensive solvation of lyophilic colloidal sols, which form a protective layer outside it which prevents it from forming associated colloids. Lyophilic colloidal sols also protect lyophobic colloidal sols from precipitation by the action of electrolytes. This is due to the formation of a protective layer by the lyophilic sols outside lyophobic sols. Lyophilic sols are also called protective sols.
Gelatin (lyophilic) protects gold sol (lyophobic) from coagulation on the addition of a solution of sodium chloride. The protective powers of different colloidal sols are measured in terms of gold number.
Gold number is defined as the amount of protective sol in milligrams that prevents the coagulation of 10 mL of a given gold sol on adding 1 mL of a $10\%$ solution of sodium chloride. Thus, the smaller the gold number of a lyophilic sol, the greater is the protective power.

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

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

Q. Lyophilic colloidal sols are much more stable than lyophobic colloidal sols. This is due to the extensive solvation of lyophilic colloidal sols, which form a protective layer outside it which prevents it from forming associated colloids. Lyophilic colloidal sols also protect lyophobic colloidal sols from precipitation by the action of electrolytes. This is due to the formation of a protective layer by the lyophilic sols outside lyophobic sols. Lyophilic sols are also called protective sols.
Gelatin (lyophilic) protects gold sol (lyophobic) from coagulation on the addition of a solution of sodium chloride. The protective powers of different colloidal sols are measured in terms of gold number.
Gold number is defined as the amount of protective sol in milligrams that prevents the coagulation of 10 mL of a given gold sol on adding 1 mL of a $10\%$ solution of sodium chloride. Thus, the smaller the gold number of a lyophilic sol, the greater is the protective power.

Gold number of hemoglobin is 0.03. Hence 100 mL of gold sol will require what amount of hemoglobin (in g) so that gold is not coagulated by 1 mL of $10\%NaCl$ solution

1. $3\times {10}^{-3}\text{g}$
2. $3\times {10}^{-2}\text{g}$
3. $3\times {10}^{-1}\text{g}$
4. $3\times {10}^{-4}\text{g}$

Q. If the solubility product of cus is 6*10–6. Calculate the maximum molarity of CuS is aqueous solution

Q. Butter is an example of ___________ whereas milk is _________ emulsion.

Q. Which of the following statements are correct?
1. The smaller the gold number of lyophobic colloid, the larger will be its protective power.
2. Lyophilic sols, in contrast to lyophobic sols are easily coagulated on the addition of small amounts of electrolytes.
3. Ferric chloride solution is used to stop bleeding from a fresh cut because it coagulates the blood.
4. The flocculation value of arsenious sulfide sol is independent of the anion of the coagulating electrolyte.

1. 1, 2 and 3
2. 1, 3 and 4
3. 2, 3 and 4
4. 1, 2 and 4

Q. Assertion :Lyophilic colloids such as starch, gelatin etc., act as protective colloids. Reason: Protective power of lyophilic colloids is expressed in terms of gold number.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Assertion is incorrect but Reason is correct

Q. 300 mL ofgold sol is mixed with 30 mL of 10% NaCl solution. The mass of Haemoglobin in mgrequired to protect the gold sol from coagulation is (gold number of Haemoglobin is 0.03)

Q. 4Q)In Habers process, if 67.2 L N2 gas reacts with equal volume of hydrogen gas at STP, find the volume of ammonia gas produced at STP. I)44.8 mL ii)22.4 L iii)2.24 mL iv)44.8 L

Q. 0.25 gm lyophilic colloid is added to the 100 ml gold solution to prevent the coagulation on adding 1 ml 10 percent NaCl solution? What will be gold number of lyophilic colloid?

Q. The coagulation of 100 mL of a colloidal solution of gold is completely prevented by addition of 0.25 gm of a substance "X" to it before the addition of 1 mL of a 10% NaCl solution. The gold number of "X" is :

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

Q. 0.25 gm pf colloidal is added yo 100ml gold solution to prevenf the coagulation on adding 1 ml 10%NaCl solution. What will be the gold number pf lyophillic colloid

Q. The vapour density of a divalent metal chloride is 59.5 find out equivalent weight of metal nitrate

Q. The coagulation of $10{\text{cm}}^3$ of gold sol by $1\text{mL}$ 10% $NaCl$ solution is completely prevented by addition of $0.025\text{g}$ of starch to it. The gold number of starch is:

Q. The coagulation of $100mL$ of a colloidal solution of gold is completely prevented by adding $0.25g$ of starch to it before adding $10mL$ of $10$% $NaCl$ solution. Find out the gold number of starch.

Q. 0.25 g of lycophilic colloid is added to 100 ml gold solution to prevent the coagulation on adding 1ml 10% NaCl solution. What will be gold number of lycophilic colloid?

Q. Which of the following is lyophobic colloid?

1. Starch in water
2. Gum in water
3. Sols of Arsenic
4. Egg albumin in water

Q. The gold numbers of protective colloids A, B, C and D are $0.02,0.002,5\text{and}30$ respectively, The protective powers of $A,B,C\text{and}D$ are in the order:

1. $D>C>A>B$
2. $D>C>B>A$
3. $A>B>C>D$
4. $B>A>C>D$

Q. Gold number of protective colloids K, L, M and N are 0.7, 0.02, 0.3 and 0.002 respectively. The correct order of their protective power is

1. N < L < M < N
2. K < M < L < N
3. L < M < K < N
4. M < K < L < N

Q.

1. True
2. False

Q.

On the addition of 1 ml. of 10% solution of sodium chloride to 10 ml. of gold sol in presence of 0.025 g of starch, the coagulation is just prevented. The gold number of starch is

1. 0.25

2. 2.5

3. 25

4. 0.025

Q. Assertion :Statement-I : Borax bead test is applicable only to coloured salts.
Because Reason: Statement-II: In the borax bead test, coloured salts are decomposed to give coloured metal metaborates.

1. Statement-I is true, Statement-II is true ; Statement-II is correct explanation for Statement-I.
2. Statement-I is true, Statement-II is true ; Statement-II is NOT a correct explanation for Statement-I.
3. Statement-I is true, Statement-II is false.
4. Statement-I is false, Statement-II is true.

Q. Assertion :Micelles are formed by surfactant molecules above the critical micellar concentration (CMC). Reason: The conductivity of a solution having surfactant molecules decreases sharply at the CMC.

1. The Assertion is true, Reason is true; Reason is a correct explanation for Assertion
2. The Assertion is true, Reason is true; Reason is not a correct explanation for Assertion
3. The Assertion is true, Reason is false
4. The Assertion is false, Reason is true

Q. Gold number of potato starch is $25$. Weight of potato starch required to prevent coagulation of $100ml$ of gold sol by the addition of $1ml$ of $10\%NaCl$ is

1. $25g$
2. $2.5g$
3. $0.005g$
4. $0.25g$