## What is gold number here?

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Dhamnekar Winod
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Location: Mumbai[Bombay],Maharashtra State,India

### What is gold number here?

0.005 g of a protective colloid is required to prevent precipitation of 1 ml of gold sol on addition of 10 ml of 10% NaCl. The gold number is

(A) 0.5
(B) 5
(C) 50
(D) 500

My answer is 0.05 milligrams. Is that correct? My computed answer is not appearing four multiple choices. So i think this question is poorly stated.
Any science consists of the following process. 1) See 2)Hear 3)Smell,if needed 4)Taste, if needed 5)Think 6)Understand 7)Inference 8)Take decision [Believe or disbelieve, useful or useless, true or false, cause or effect, any other criteria]
ChenBeier
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Location: Berlin, Germany

### Re: What is gold number here?

I would say its solution B 5. For 1 ml Goldsol 5 mg Protection colloid is needed.
Its 5 mg/ 1ml
Warner Mortensen
Jr. Member
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Joined: Mon Jul 26, 2021 4:13 am

### Re: What is gold number here?

Amount of starch added = 0.005 x1000
= 0.5 mg
Prevent Coagulation by addition of 1ml of colloid = 5/100 x 10
= 0.5 mg
Hence the gold number is 0.5 mg
The gold number is the minimum weight of a protective colloid required to prevent the coagulation of 10 ml of a standard hydro gold solution when 1 ml of a 10% sodium chloride solution is added to it.
ChenBeier
Distinguished Member
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Joined: Wed Sep 27, 2017 7:25 am
Location: Berlin, Germany

### Re: What is gold number here?

If this is the calculation, then

0.005 * 1000 = 5 not 0.5 isn't it.

The result would be 5, answer B
Dhamnekar Winod
Sr. Staff Member
Posts: 192
Joined: Sat Nov 21, 2020 10:14 am
Location: Mumbai[Bombay],Maharashtra State,India