Question

The gold number of gelatin is $0.01$. Calculate the amount of gelatin to be added to ${\rm{1000}}\;{\rm{mL}}$ of a colloidal sol of gold to prevent its coagulation before adding ${\rm{1}}\;{\rm{mL}}$ of $10\% $ NaCl solution.
A. $2$
B. $1$
C. $4$
D. $5$

Answer 1

Hint: We know that the gold number of gelatin is given which is $0.01$. Basically, this gold number shows that $0.01$ mg gelatin is needed to be added to ${\rm{10}}\;{\rm{mL}}$ of gold sol in case of $10\% $ NaCl solution. So, by using this value we can easily calculate for ${\rm{1000}}\;{\rm{mL}}$.

Complete step by step answer:
The coagulation is that process which shows the changes in the circulating system and generally forms an insoluble gel. The main steps involved in that process are activation, adhesive of blood platelets, the deposition and maturation of species named as fibrin.
Sol is one of the colloids which can usually be made out of tiny solid particles which is present in a continuous liquid medium. Sols are relatively stable, and they generally show the Tyndall effect.
The general mathematical way is used for solving this question.
Given, the gold number of gelatin is $0.01$.
Usually, this suggests that $0.01$ mg gelatin is needed to be added to ${\rm{10}}\;{\rm{mL}}$ of gold sol in order to completely prevent the coagulation of ${\rm{1}}\;{\rm{mL}}$ of $10\% $ NaCl solution.
The gelatin which is required to add to the ${\rm{1000}}\;{\rm{mL}}$ of gold sol to prevent coagulation is shown below.
$\dfrac{{0.01 \times 1000}}{{10}} = 1\;{\rm{mg}}$
Thus, the amount of gelatin to be added to ${\rm{1000}}\;{\rm{mL}}$ of a colloidal sol of gold to prevent its coagulation before adding ${\rm{1}}\;{\rm{mL}}$ of $10\% $ NaCl solution.is ${\rm{1}}\;{\rm{mg}}$.

So, the correct answer is “Option B”.

Note:
The gelatin is one of the luminous, colorless and tasteless food ingredients which generally are derived from the species that is collagen obtained from the animal body.